Map data processing device, interference evaluation system, map data processing method and program

Abstract

This map data processing device comprises: a map information acquiring unit which acquires map data showing a map in which it is possible to identify the positional relationship between the position of an edge of a road and the position of the center of the road; an area information acquiring unit which acquires information showing an area to be evaluated in the map; an area sectioning unit which sections the area to be evaluated into a grid by dividing along dividing lines at a prescribed spacing; and a road width calculating unit which, on the basis of the position of the edge of the road and the position of the center of the road in each of the grid squares, calculates an average road width of the road in the area to be evaluated.

Description

[Technical Field]

[0001] The present invention relates to a map data processing device, an interference evaluation system, a map data processing method, and a program. [Background technology]

[0002] In recent years, the spread of a wide variety of wireless communication systems has led to a shortage of frequency resources. Because frequency resources are limited, wireless communication systems require coordination among users to avoid radio wave interference (hereinafter simply referred to as "interference") between the radio waves used by multiple users. Furthermore, telecommunications carriers that build wireless communication infrastructures must also coordinate when new wireless communication systems, either their own or those of other companies, are installed to avoid interference with the radio waves used by their existing wireless communication systems.

[0003] Thus, in order to effectively utilize limited frequency resources, a system design that takes into account interference occurring between multiple wireless stations is required. Generally, when a wireless communication system is constructed, an interference assessment that quantitatively evaluates such interference is performed in advance, and the system design is performed based on the assessment results. To perform such interference assessment, it is necessary to perform interference calculations based on information about wireless communication by an interfering station that causes interference, information about wireless communication by an interfered station that receives interference, and the propagation loss of the interference wave that is attenuated due to various environmental conditions between the interfering station and the interfered station. The environmental conditions referred to here include, for example, the distance between the interfering station and the interfered station, the topography, the presence of structures, and the width of the road.

[0004] Conventionally, such interference assessment has been performed by experts with specialized knowledge and skills regarding radio wave propagation loss, specifications of wireless communication devices, etc., using, for example, general-purpose spreadsheet software, etc. An example of conventional interference assessment using general-purpose spreadsheet software, etc. will be briefly described below.

[0005] For example, Fig. 37 is a diagram showing an example of an interference calculation screen using general-purpose spreadsheet software. As shown in Fig. 37, the left portion of the interference calculation screen lists a plurality of parameters (hereinafter referred to as "interference calculation parameters") used in interference calculation. Each interference calculation parameter item is classified into one of five categories: "transmitting side specifications," "receiving side specifications," "transmitting power structure," "path loss," and "receiving side power structure." Appropriate values ​​must be set for these listed interference calculation parameters according to each specific case of interference evaluation.

[0006] Also, on the right side of the interference calculation screen shown in FIG. 37, a link design graph is displayed, which shows the results of the interference calculation as a line graph. This link design graph is generated based on the values ​​set for each interference calculation parameter listed on the left side of the interference calculation screen. As shown in FIG. 37, the link design graph shows, from left to right, the power values ​​of transmission power calculated based on the values ​​of the interference calculation parameters for the "interfering transmitting side system," "path loss / additional loss," and "interfered receiving side system." This shows the transmission power structure. Furthermore, the link design graph shows the value of the interference margin that takes into account the allowable INR (Interference-to-Noise Ratio) for the system noise power. This allows the amount of under-interference suppression to be calculated, which is the difference between the power value of the calculated transmission power and the value of the interference margin.

[0007] On the interference calculation screen shown as an example in Figure 37, the calculated power value of the transmission power does not satisfy the value of the interference margin as a result of the interference calculation. In other words, the amount of interference power that the interfered station can tolerate exceeds the allowable range with respect to the influence of interference that the interfered station receives from the interfering station. Therefore, in this case, it is determined that the interfering station and the interfered station cannot be used (shared) at the same time. As a result, on the interference calculation screen shown in Figure 37, an "x" mark is displayed in the display area of ​​the "Determination Result" item, indicating that sharing is not possible.

[0008] Also, for example, Fig. 38 is a diagram showing another example of an interference calculation screen using general-purpose spreadsheet software. As shown in Fig. 38, a plurality of interference calculation parameter items are listed on the left side of the interference calculation screen. Each interference calculation parameter item is classified into one of four categories: "transmitting side parameters," "receiving side parameters," "path loss," and "receiving side power structure." As described above, appropriate values ​​must be set for these listed interference calculation parameters in accordance with each specific case of interference evaluation.

[0009] However, in the case of the interference calculation screen shown in Fig. 38, the transmitting device indicated by the "transmitter specifications" displayed as a category is not a wireless communication device but an electrical appliance or the like that emits unwanted waves. In other words, Fig. 38 shows an example of an interference calculation screen when performing a link design by regarding the unwanted waves emitted by electrical appliances or the like as interference waves. In this example, the value of the transmission power density of the radiated unwanted waves is used as the interference calculation parameter of the "transmitter specifications" for interference calculation.

[0010] Also, a link design graph is displayed on the right side of the interference calculation screen shown in Fig. 38, similar to Fig. 37. On the interference calculation screen shown as an example in Fig. 38, the calculation result of the interference calculation shows that the noise power on the transmitting side is smaller than the allowable interference power on the receiving side. In other words, in this case, the receiving side can tolerate the influence of interference from the transmitting side. Therefore, in this case, it is determined that the transmitting side device and the receiving side device can be used (shared) simultaneously. As a result, on the interference calculation screen shown in Fig. 38, a "○" mark indicating that sharing is possible is displayed in the display area of ​​the "Determination Result" item.

[0011] In contrast to conventional interference assessment techniques that use such general-purpose spreadsheet software, interference assessment software that allows even people without specialized knowledge or skills in wireless communications to perform interference assessment has come into use in recent years. For example, the interference assessment software discussed in Non-Patent Document 1 and described in Non-Patent Document 4 can assist users in interference assessment by presenting them with an appropriate radio wave propagation formula from among multiple radio wave propagation formulas that are used to calculate the degree of interference. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Patent No. 6908854 [Non-patent literature]

[0013] [Non-Patent Document 1] "Interference Assessment Software to Determine Sharing Conditions of Wireless Systems: Technology for Dramatically Smarter Operation", Tsukuba Forum 2022, Exhibit No. 2-03, NTT Exhibit, May 18-19, 2022 [Non-patent document 2] Fujio Kobayashi, Masatoshi Mito, Takashi Ozeki, “Road Extraction and Restoration from Urban Maps,” Bulletin of the Faculty of Engineering, Fukuyama University, Vol. 23, pp. 67-72, October 1999, [Retrieved January 11, 2023], Internet (URL: https: / / cir.nii.ac.jp / crid / 1050845762531764864) [Non-patent document 3] Jin Yamauchi, Akira Tomono, Akihiro Kanagawa, "Road Map Creation Probe System by Shape Integration Based on Roadside Color Information", Transactions of Information Processing Society of Japan, Vol. 52, No. 1, pp. 257-268, January 2011 [Non-patent document 4] “Tsukuba History: Wireless Access Technology Interference Assessment Software,” NTT Access Service Systems Laboratories, 2018, [Retrieved January 11, 2023], Internet (URL: https: / / www.rd.ntt / as / history / wireless / wi0512.html) Summary of the Invention [Problem to be solved by the invention]

[0014] As mentioned above, the interference assessment software described in Non-Patent Document 1 and discussed in Non-Patent Document 4 can present the user with an appropriate radio wave propagation equation. However, in order to calculate this radio wave propagation equation, it is necessary to input various data values ​​obtained from map information into the variables of the radio wave propagation equation (hereinafter referred to as "propagation equation parameters"). An example of such a propagation equation parameter is "average road width." Road width is highly correlated with the distance between multiple buildings in the area where the wireless stations to be evaluated for interference are installed, and the density of multiple buildings in the area. Therefore, the degree of interference varies greatly depending on the width of the road between the wireless stations. For this reason, in interference assessment, it is desirable to input a more accurate value of the average road width into the propagation equation parameter.

[0015] For example, the technology described in Non-Patent Document 2 can extract roads from city maps and repair missing portions. Furthermore, for example, the dynamic map creation system described in Non-Patent Document 3 can create maps using an on-board camera and a GPS receiver, with ordinary vehicles as probe cars. However, these conventional technologies are all technologies for creating road maps, and are not technologies for calculating average road widths. If an attempt were made to calculate average road widths using the conventional technologies described in Non-Patent Document 2 or Non-Patent Document 3, it is expected that the amount of calculations would be enormous.

[0016] This is because, in general, many places, especially urban areas, have many roads, and even within the same road, the road width often varies from point to point. Therefore, in conventional techniques, for example, it is necessary to visually extract from a map many points where the road width changes for each of the many roads, manually measure the road width at the extracted points, and then calculate the average road width for each road, which requires an enormous amount of calculation.

[0017] In view of the above circumstances, an object of the present invention is to provide a map data processing device, an interference evaluation system, a map data processing method, and a program that can calculate the average road width from map information with higher accuracy while suppressing an increase in the amount of calculation. [Means for solving the problem]

[0018] One aspect of the present invention is a map data processing device that includes a map information acquisition unit that acquires map data showing a map that can identify the positional relationship between the positions of the edges of a road and the position of the center of the road; a range information acquisition unit that acquires information showing an evaluation target range on the map; a range division unit that divides the evaluation target range into a grid by dividing it with dividing lines at a predetermined interval; and a road width calculation unit that calculates the average road width of the roads that exist within the evaluation target range based on the positions of the edges of the road and the positions of the center of the road that exist within each grid.

[0019] Another aspect of the present invention is an interference evaluation system having a map data processing device and an interference evaluation device, wherein the map data processing device comprises: a map information acquisition unit that acquires map data showing a map on which the positional relationship between the positions of road edges and the position of the center of the road can be identified; a range information acquisition unit that acquires information showing an evaluation target range on the map; a range division unit that divides the evaluation target range into a grid by dividing the evaluation target range with dividing lines at predetermined intervals; a road width calculation unit that calculates an average road width of the roads that exist within the evaluation target range based on the positions of the road edges and the positions of the road centers that exist within each grid; and a road width output unit that outputs the value of the average road width of the roads to the interference evaluation device, and the interference evaluation device comprises: a road width acquisition unit that acquires the value of the average road width of the road output from the map data processing device; and a propagation loss calculation unit that inputs the value of the average road width of the road into a variable of a formula for calculating the propagation loss of radio waves propagating between radio base stations to calculate the propagation loss.

[0020] Another aspect of the present invention is a map data processing method executed by a computer, the map data processing method including: a map information acquisition step of acquiring map data showing a map capable of identifying the positional relationship between the positions of the edges of a road and the positions of the centers of the roads; a range information acquisition step of acquiring information showing an evaluation target range on the map; a range division step of dividing the evaluation target range into a grid by dividing lines at predetermined intervals; and a road width calculation step of calculating an average road width of the roads existing within the evaluation target range based on the positions of the edges of the roads and the positions of the centers of the roads existing within each grid.

[0021] Another aspect of the present invention is a program that causes a computer to function as the map data processing device described above. [Effects of the Invention]

[0022] The present invention makes it possible to more accurately calculate the average road width from map information while suppressing an increase in the amount of calculation. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 2 is a diagram showing an example of a map and an evaluation range used in calculating an average road width by the map data processing device 100 according to the first embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of a region around one of intersection points i that exists within the evaluation range e of FIG. 1. [Figure 3] 1 is a block diagram showing a functional configuration of a map data processing device 100 according to a first embodiment of the present invention. [Figure 4] 3 is a flowchart showing the operation of the map data processing device 100 in the first embodiment of the present invention. [Figure 5] FIG. 2 is an enlarged view of a region around one of intersection points i that exists within the evaluation range e of FIG. 1. [Figure 6] FIG. 2 is a block diagram showing the functional configuration of a map data processing device 100a according to a modified example of the first embodiment of the present invention. [Figure 7] 10 is a flowchart showing the operation of the map data processing device 100a in a modified example of the first embodiment of the present invention. [Figure 8] FIG. 10 is a diagram showing an example of a map mi and an evaluation range e used in calculating the average road width by a map data processing device 100b according to a second embodiment of the present invention. [Figure 9] FIG. 10 is a block diagram showing the functional configuration of a map data processing device 100b according to a second embodiment of the present invention. [Figure 10] 6 is a flowchart showing the operation of the map data processing device 100 in the second embodiment of the present invention. [Figure 11] 1 is a schematic diagram showing an outline of the functions of an interference evaluation device 1 according to an embodiment of the present invention. [Figure 12] 1 is a block diagram showing the functional configuration of an interference evaluation device 1 according to an embodiment of the present invention. [Figure 13] 1 is a schematic diagram showing an example of a main menu screen displayed by an interference evaluation device 1 according to an embodiment of the present invention. [Figure 14]1 is a function list for explaining the functions of each menu displayed on a main menu screen generated by the interference evaluation device 1 according to one embodiment of the present invention. [Figure 15] 1 is a schematic diagram showing an example of a station DB management screen displayed by an interference evaluation device 1 according to an embodiment of the present invention. [Figure 16] 1 is a schematic diagram showing an example of a station DB editing screen displayed by an interference evaluation device 1 according to an embodiment of the present invention. FIG. [Figure 17] 1 is a diagram for explaining screen transitions of a display screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. [Figure 18] 1 is a schematic diagram showing an example of an execution condition specification screen for map-based interference evaluation displayed by the interference evaluation device 1 according to one embodiment of the present invention. FIG. [Figure 19] 1 is a schematic diagram showing an example of a history selection screen in map-based interference evaluation displayed by the interference evaluation device 1 according to one embodiment of the present invention. FIG. [Figure 20] 1 is a schematic diagram showing an example of a station selection screen displayed by an interference evaluation device 1 according to an embodiment of the present invention. [Figure 21] 1 is a schematic diagram showing an example of an execution condition designation screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. FIG. [Figure 22] 1 is a schematic diagram showing an example of an execution condition designation screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. FIG. [Figure 23] 1 is a schematic diagram showing an example of a calculation result display screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. [Figure 24] 1 is a schematic diagram showing an example of an interference evaluation result screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. [Figure 25] 1 is a schematic diagram showing an example of a calculation result screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. [Figure 26] 1 is a schematic diagram showing an example of an interference evaluation result screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. [Figure 27] 1 is a schematic diagram showing an example of a calculation result display screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. [Figure 28] 2 is a screen transition diagram showing transition of screens displayed by the interference evaluation device 1 according to one embodiment of the present invention. FIG. [Figure 29] 2 is a screen transition diagram showing transition of screens displayed by the interference evaluation device 1 according to one embodiment of the present invention. FIG. [Figure 30] 1 is a schematic diagram showing an example of an interference evaluation result screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. [Figure 31] 2 is a screen transition diagram showing transition of screens displayed by the interference evaluation device 1 according to one embodiment of the present invention. FIG. [Figure 32] 2 is a screen transition diagram showing transition of screens displayed by the interference evaluation device 1 according to one embodiment of the present invention. FIG. [Figure 33] 1 is a schematic diagram showing an overview of cooperation between an interference evaluation device 1 and a map data processing device in one embodiment of the present invention. [Figure 34] 10 is a flowchart showing the flow of a cooperative process between the interference evaluation device 1 and the map data processing device in one embodiment of the present invention. [Figure 35] 2 is a screen transition diagram showing transition of screens displayed by the interference evaluation device 1 according to one embodiment of the present invention. FIG. [Figure 36] 1 is a schematic diagram showing an example of an execution condition designation screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. FIG. [Figure 37] FIG. 10 is a diagram showing an example of an interference calculation screen using general-purpose spreadsheet software. [Figure 38] FIG. 10 is a diagram showing another example of an interference calculation screen using general-purpose spreadsheet software. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, a map data processing device, an interference evaluation system, a map data processing method, and a program according to embodiments will be described with reference to the drawings. In the following description, three types of data processing devices according to an embodiment of the present invention will first be described as a first embodiment, a modified example of the first embodiment, and a second embodiment. After that, an interference evaluation device 1 according to an embodiment of the present invention, which cooperates with any of these three types of data processing devices to form an interference evaluation system, will be described.

[0025] First Embodiment The basic concept of the method for calculating the average road width performed by the map data processing device 100 in the first embodiment of the present invention will be described below.

[0026] The map data processing device 100 acquires map data, and then specifies the range within the acquired map data for which the average road width is to be calculated, i.e., the range to be subjected to interference evaluation (hereinafter referred to as the "evaluation range"), and calculates the average road width of roads present within the evaluation range. In the first embodiment, the map data input to the map data processing device 100 includes at least information indicating the positions of both side edges of each road (hereinafter also referred to as "road edges") and a line indicating the center position of the road edges on both sides (hereinafter referred to as the "road centerline"). The map data processing device 100 in the first embodiment calculates the average road width more simply based on the positions of the intersections of the road centerlines and lines (hereinafter referred to as "dividing lines") that divide the evaluation range into smaller grid-like (mesh-like) areas, and the position of the road edge on one side.

[0027] 1 is a diagram showing an example of a map and an evaluation range used in calculating an average road width by a map data processing device 100 according to a first embodiment of the present invention. The map data processing device 100 acquires map information from, for example, an external system via a network. Alternatively, the map data processing device 100 reads map information stored in, for example, a storage medium.

[0028] FIG. 1 shows a map mi based on the above map information. As an example, the map mi shown in FIG. 1 is a map of a part of an urban area. On the map mi, lines representing roads, lines representing the outlines of structures such as buildings, lines representing paths in parks, etc. are shown as solid lines. On the map mi shown in FIG. 1, road edges r indicating the edges of the road and road centerlines c indicating the position of the center of the road (i.e., a position that is an equal distance from both road edges) are shown as solid lines. For example, map information provided by the Geospatial Information Authority of Japan can be used as map information that can identify the positions of such road edges and road centerlines.

[0029] Furthermore, on the map mi, an evaluation target range e, which indicates the range for calculating the average road width, is indicated by a dashed line. The evaluation target range e is specified, for example, by a user who performs interference evaluation. The evaluation target range e is specified, for example, using a user interface (operation input unit) provided in the map data processing device 100. Alternatively, the evaluation target range e is specified, for example, using an interference evaluation device that performs processing related to interference evaluation, and information indicating the specified evaluation target range e is input to the map data processing device 100 via a network. The interference evaluation device will be described in detail later.

[0030] Furthermore, on the map mi, a plurality of delimiting lines d are indicated by dotted lines. The delimiting lines d are lines that divide the evaluation target range e into smaller grid-like (mesh-like) areas at equal intervals. The interval between adjacent delimiting lines d is set, for example, so that the size of one grid (mesh) created by the delimiting lines d is smaller than the size of a section existing in the map mi (or in the evaluation target range e). A section here refers to an area surrounded by roads (for example, an area where buildings, parks, etc. exist). That is, in the first embodiment, the size of the grid created by the delimiting lines d is determined, for example, according to the size of a section included in the map mi.

[0031] Specifically, for example, a user performing interference assessment visually identifies the section with the smallest area among the sections included in the assessment target range e. Then, the user uses a user interface (operation input unit) provided in the map data processing device 100 to adjust the spacing of the delimiting lines d so that the size of the grid formed by the delimiting lines d is smaller than the size of the identified section. For example, if the identified section is rectangular, the user adjusts the spacing of the delimiting lines d so that the length of the side of the grid formed by the delimiting lines d is shorter than the length of the shorter side of the section.

[0032] Alternatively, for example, the map data processing device 100 extracts each of the sections included in the evaluation range e by image analysis and identifies the section with the smallest area. Existing image recognition technology can be used for the image analysis. It is possible to further improve the extraction accuracy by performing machine learning on the process of extracting sections from the map. The map data processing device 100 then adjusts the spacing of the delimiting lines d so that the size of the grid formed by the delimiting lines d is smaller than the size of the sections identified by image analysis.

[0033] By setting the size of one grid (mesh) formed by the delimiting lines d to be smaller than the size of the smallest block in the map mi (or the evaluation target area e), the map data processing device 100 can ensure that all road center lines c existing within the map mi (or the evaluation target area e) intersect with the delimiting lines d. For example, there may be cases where the length of a road, such as a back alley, existing within a block is the same as one side of the block. Even in such cases, by setting the size of one grid (mesh) formed by the delimiting lines d to be smaller than the size of the smallest block, the road center line c and the delimiting lines d will always intersect at one or more locations. Therefore, the map data processing device 100 in this embodiment can calculate the road width even for a short road whose length is the same as the length of one side of a small block.

[0034] In FIG. 1, the spacing between the delimiting lines d is shown wider than it actually is to make the drawing easier to see and the explanation easier to understand. In FIG. 1, it is assumed that there are no narrow roads, such as back alleys, and road center lines c are not shown on narrow roads. In FIG. 1, the spacing between the delimiting lines d is set by recognizing the area surrounded only by wider main roads as a section. Therefore, in order to more accurately calculate the average road width of all roads included in the evaluation range e, it is necessary to recognize the area surrounded by narrow roads, such as back alleys, as a section and set the spacing between the delimiting lines d narrower. The more accurate the average road width, the more accurate the interference assessment.

[0035] Once the size of the grid formed by the evaluation range e and the delimiting lines d in the map mi has been determined, the map data processing device 100 extracts all intersection points i, which are positions within the evaluation range e where the road center line c intersects with the delimiting lines d. In Figure 1, the intersection points i are indicated by open circles. In the case of the evaluation range e illustrated in Figure 1, as shown, there are 36 locations that become intersection points i.

[0036] When intersections i within the evaluation range e are extracted, the map data processing device 100 measures the distance from the position of each intersection i to the shortest road edge r. Figure 2 is an enlarged view of the area surrounding one of the intersections i present within the evaluation range e in Figure 1. Figure 2 shows road edges r on both sides of the road, a road centerline c at a position midway between the road edges r on both sides, a dividing line d, and one intersection i where the road centerline c and the dividing line d intersect.

[0037] The map data processing device 100 calculates the shortest distance L from the intersection point i to the road edge r. Specifically, for example, when a line is extended from the intersection point i in a direction perpendicular to the road center line c at the position of the intersection point i, the map data processing device 100 identifies the position where the line intersects with the road edge r. Note that there are two directions perpendicular to the road center line c, and the map data processing device 100 arbitrarily selects either direction.

[0038] Then, the map data processing device 100 measures the distance between the identified position and the intersection point i, and sets the measurement result value as the shortest distance L. Furthermore, the map data processing device 100 calculates the road width at the intersection point i by doubling the value of the measured shortest distance L.

[0039] If the position of the road centerline c is exactly equidistant from the positions of the road edges r on both sides, the shortest distance L from intersection i to the road edge r should be the same regardless of which side of the road edge r is measured from intersection i. However, on an actual map, there may be some error in the distance between the road centerline c and each of the road edges r on both sides.

[0040] However, the map data processing device 100 in the first embodiment considers that there is no error in the distance between the road centerline c and each of the road edges r on both sides. The map data processing device 100 then arbitrarily selects one of two directions perpendicular to the road centerline c, measures the distance, and considers the measured distance doubled to be the road width. With this configuration, the map data processing device 100 in the first embodiment can measure the road width at the position of one intersection i in just one measurement, thereby reducing the amount of processing required for measurement.

[0041] Furthermore, by having such a configuration, even if information indicating the position of one road edge r is missing, the map data processing device 100 in the first embodiment can calculate the road width based on the position of the other road edge r. For example, as shown in Figure 1, depending on the position of the intersection i, the line of one road edge r may be hidden by the name of a place or facility, and the information indicating the position of the road edge r may be missing.

[0042] In such a case, the map data processing device 100 in the first embodiment first arbitrarily selects one of the two directions perpendicular to the road center line c, and if information indicating the position of the road edge r in the selected direction is missing, it selects the other direction again and measures the shortest distance L between the intersection point i and the road edge r.

[0043] The map data processing device 100 in the first embodiment measures the shortest distance L for each of the positions of all intersections i that exist within the evaluation target range e, and calculates the road width by doubling the measurement result. Therefore, for example, in the evaluation target range e of the map mi illustrated in Fig. 1, there are 36 intersections i, and therefore the map data processing device 100 performs measurement processing 36 times.

[0044] The map data processing device 100 adds up all the measured road width values. Then, the map data processing device 100 calculates the average road width by dividing the added value by the number of intersections i. Therefore, in the case of the evaluation target range e of the map mi illustrated in FIG. 1, since there are 36 intersections i, the average road width value within the evaluation target range e is calculated by dividing the total value of all the measured road widths by 36.

[0045] As mentioned above, in order to make the drawing easier to see and the explanation easier to understand, it is assumed in Figure 1 that there are no narrow roads, such as back alleys. However, in reality, it is desirable to calculate the average road width taking into account the existence of narrow roads. Below, we will explain how much the amount of calculation increases when the existence of narrow roads is taken into account.

[0046] The amount of calculation required to calculate the average road width is proportional to the number of intersections i. Here, the number of intersections i is represented as Ci. In other words, in the case of the map mi, evaluation range e, and interval between the dividing lines d shown in Figure 1, if the number of intersections i in Figure 1 is represented as Ci_fig1, then Ci_fig1 = 36.

[0047] If the partitions are identified taking into account the existence of narrower roads, and the interval between the dividing lines d is set so that the size of the grid is smaller than that of the identified partitions, the interval will be 1 / Nm longer than in the case of Figure 1. In this case, the number of grids will be Nm 2 Furthermore, the number of narrow roads that are considered not to exist in the example shown in Figure 1 is Nr times the number of roads that are considered to exist in Figure 1. In such a case, the number Ci of intersections i can be expressed by the following equation (1):

[0048] Ci=Nr×Nm 2 ×Ci_fig1 ···(1)

[0049] Here, considering the number of back alleys for one main road in a typical urban area, if we assume Nr = 5 and Nm = 4, then the number of intersections i can be found to be approximately 2,880 using the following equation (2).

[0050] Ci=5×4 2 ×36=2880 (2)

[0051] Therefore, when the evaluation range e is as large as shown in FIG. 1, the number of intersections i is estimated to be no more than 5,000. Considering the computational capabilities of modern information processing devices, increasing the above 36 measurement processes to 5,000 calculation processes is not expected to significantly increase the processing time. As shown in (1) above, the number of intersections i is at most on the order of the square of Nm. Therefore, the number of calculation processes is also at most on the order of the square of Nm, and considering this point, it is not expected to significantly increase the processing time.

[0052] 2 shows, as an example, the measurement of road width at the intersection i of a road edge r extending in a substantially horizontal direction and a delimiting line d extending in a vertical direction. Of course, the same method can also be used to measure road width conversely at the intersection i of a road edge r extending in a substantially vertical direction and a delimiting line d extending in a horizontal direction. There are also other cases where a road edge r extending in a substantially horizontal direction intersects with a delimiting line d also extending in a horizontal direction, or where a road edge r extending in a substantially vertical direction intersects with a delimiting line d also extending in a vertical direction. Furthermore, if the road is curved or meandering, the road edge r and the vertical and horizontal delimiting lines d may intersect irregularly at close distances from each other.

[0053] In such a case, the map data processing device 100 may be configured to narrow down the intersection points i for which the road width is to be calculated according to certain rules established in advance. For example, for a road in which the road edge r intersects with both a vertical delimiting line d and a horizontal delimiting line d, the map data processing device 100 may be configured to calculate the road width only for the intersection points i between the delimiting line d in either one direction (vertical or horizontal) and the road edge r. Also, for a road in which the road edge r intersects with both a vertical delimiting line d and a horizontal delimiting line d, the map data processing device 100 may be configured to calculate the road width only for the intersection points i between the delimiting line d in the direction with the greater number of intersection points i and the road edge r.

[0054] Furthermore, for example, in the case of a road in which both a vertical delimiting line d and a horizontal delimiting line d intersect with a road edge r, the map data processing device 100 may calculate the road width only for the intersection point i between the vertical delimiting line d and the road edge r if the angle of the line connecting the positions of the two ends of the road is closer to the horizontal direction, and may calculate the road width only for the intersection point i between the horizontal delimiting line d and the road edge r if the angle of the line connecting the positions of the two ends of the road is closer to the vertical direction. By being configured as described above, the map data processing device 100 in the first embodiment can suppress an increase in the amount of calculation required to calculate the average road width.

[0055] [Functional configuration of map data processing device] The following describes the functional configuration of the map data processing device 100. Fig. 3 is a block diagram showing the functional configuration of the map data processing device 100 according to the first embodiment of the present invention.

[0056] As shown in FIG. 3, the map data processing device 100 includes a map data acquisition unit 101, a road information extraction unit 102, an evaluation range designation unit 103, a delimiter line spacing designation unit 104, an intersection extraction unit 105, a distance measurement unit 106, a road width calculation unit 107, a road width information storage unit 108, an average road width calculation unit 109, and an average road width information output unit 110.

[0057] The map data acquisition unit 101 acquires map information and outputs the acquired map information to the road information extraction unit 102.

[0058] The map indicated by this map information may be, for example, a map of a pre-defined range limited to the area for which interference assessment is to be performed, or may be a map of the entire general area (for example, an overall map of the whole country, region, prefecture, city, town, village, etc.).

[0059] The map shown by this map information must include at least information indicating the positions of the road edge r and road center line c of the road. Alternatively, the map shown by this map information must include at least information necessary to identify the positions of the road edge r and road center line c of the road. As such map information that can identify the positions of the road edge and road center line, map information provided by the Geospatial Information Authority of Japan, for example, can be used. Hereinafter, information indicating the positions of the road edge r and road center line c of the road, or information necessary to identify the positions of the road edge r and road center line c of the road, will also be referred to as "road information."

[0060] The map data acquisition unit 101 acquires map information from, for example, an external device via a network. The external device here is, for example, an interference assessment device that performs interference assessment using the average road width value calculated by the map data processing device 100. Alternatively, the external device here is, for example, a server device that publishes a website that provides map information via the Internet (for example, the website of the Geospatial Information Authority of Japan). Alternatively, the map data processing device 100 acquires map information by, for example, reading map information stored in a storage medium. The storage medium here is, for example, an optical disk, a magnetic disk, or a semiconductor memory.

[0061] The road information extraction unit 102 acquires the map information output from the map data acquisition unit 101. The road information extraction unit 102 extracts road information from the acquired map information. The road information extraction unit 102 outputs the acquired map information and the extracted road information to the evaluation target range designation unit 103.

[0062] The evaluation target range designation unit 103 acquires the map information and road information output from the road information extraction unit 102. The evaluation target range designation unit 103 also acquires information indicating the evaluation target range e. The evaluation target range designation unit 103 outputs the acquired map information, road information, and information indicating the evaluation target range e to the delimiter line interval designation unit 104.

[0063] The evaluation target range designation unit 103 acquires information indicating the evaluation target range e, for example, from an external device or the like via a network. The external device here is, for example, an interference evaluation device or the like that performs interference evaluation using the average road width value calculated by the map data processing device 100.

[0064] Alternatively, the evaluation target range designation unit 103 acquires information indicating the evaluation target range e that is input by, for example, a user operating an operation input unit (not shown) included in the map data processing device 100. In this case, for example, the evaluation target range designation unit 103 displays a map mi based on the acquired map information and road information on a display unit (not shown) included in the map data processing device 100. The user performs an operation to designate the evaluation target range e using the operation input unit (not shown) while referring to the map mi displayed on the display unit (not shown). Specifically, for example, the user designates the evaluation target range e by adjusting the size of a rectangular area that will become the evaluation target range e on the map mi displayed on the display unit (not shown).

[0065] The operation input unit (not shown) is configured by, for example, input devices such as a keyboard, a mouse, and input buttons, or a combination of these input devices. The operation input unit (not shown) may be, for example, an input / output device such as a touch panel integrated with a display unit (not shown). The display unit (not shown) is, for example, a display device such as a liquid crystal display (LCD), an organic electroluminescence (EL) display, or a cathode-ray tube (CRT) display. The operation input unit (not shown) and the display unit (not shown) may be built into the map data processing device 100, or at least one of the operation input unit (not shown) and the display unit (not shown) may be an external device.

[0066] The delimiting line interval designation unit 104 acquires the map information, road information, and information indicating the evaluation target range e output from the evaluation target range designation unit 103. The delimiting line interval designation unit 104 also acquires information indicating the interval between delimiting lines d. The delimiting line interval designation unit 104 may also acquire information indicating the size of the grid (mesh) formed by the delimiting lines d. The delimiting line interval designation unit 104 outputs the map information, road information, information indicating the evaluation target range e, and information indicating the interval between delimiting lines d to the intersection extraction unit 105.

[0067] The delimiting line interval designation unit 104 acquires information indicating the intervals of the delimiting lines d, for example, from an external system or the like via a network. The external system referred to here is, for example, an interference evaluation device that performs interference evaluation using the average road width value calculated by the map data processing device 100. As described above, the intervals of the delimiting lines d based on the information acquired here are intervals adjusted so that the size of the grid formed by the delimiting lines d is smaller than the size of the sections within the map mi (or within the evaluation target range e).

[0068] Alternatively, the delimiting line interval designation unit 104 acquires information indicating the intervals of the delimiting lines d that is input by, for example, a user operating an operation input unit (not shown) included in the map data processing device 100. In this case, for example, the delimiting line interval designation unit 104 causes a map mi based on the acquired map information and road information, and an evaluation target range e based on the acquired information, to be displayed on a display unit (not shown) included in the map data processing device 100. The user performs an operation to designate the intervals of the delimiting lines d using the operation input unit (not shown) while referring to the map mi and the evaluation target range e displayed on the display unit (not shown).

[0069] Specifically, for example, the user performs an operation to adjust the spacing of the delimiting lines d on the map mi displayed on the display unit (not shown). Here, the user visually or otherwise identifies the smallest section on the map mi displayed on the display unit (not shown) (or within the evaluation target range e), and adjusts the spacing of the delimiting lines d so that the size of the grid formed by the delimiting lines d is smaller than the size of the identified section.

[0070] The intersection extraction unit 105 acquires the map information, road information, information indicating the evaluation target range e, and information indicating the intervals between the delimiter lines d, which are output from the delimiter line interval designation unit 104. Based on this acquired information, the intersection extraction unit 105 identifies the positions of all road center lines c and delimiter lines d that exist within the evaluation target range e. The intersection extraction unit 105 extracts all intersections i, which are positions where the identified road center lines c intersect with the delimiter lines d. The intersection extraction unit 105 identifies the positions of all extracted intersections i. The intersection extraction unit 105 outputs the map information, road information, information indicating the evaluation target range e, and information indicating the positions of all intersections i to the distance measurement unit 106.

[0071] The distance measurement unit 106 acquires the map information, road information, information indicating the evaluation target range e, and information indicating the positions of all intersections i output from the intersection extraction unit 105. Based on the acquired map information, road information, and information indicating the evaluation target range e, the distance measurement unit 106 identifies the positions of road edges r of all roads existing within the evaluation target range e. For each intersection i, the distance measurement unit 106 measures the shortest distance L between the position of the intersection i and the road edge r. The distance measurement unit 106 outputs the value of the shortest distance L at the position of each intersection i and information indicating the number of intersections i to the road width calculation unit 107.

[0072] Specifically, for example, when a line is extended from intersection point i in a direction perpendicular to the road center line c at the position of intersection point i, the distance measurement unit 106 identifies the position where the line intersects with the road edge r. Note that there are two directions perpendicular to the road center line c, and the map data processing device 100 arbitrarily selects either direction. Then, the distance measurement unit 106 measures the distance between the identified position and intersection point i, and the measurement result value is set as the shortest distance L.

[0073] The road width calculation unit 107 acquires the value of the shortest distance L at the position of each intersection i and information indicating the number of intersections i, which are output from the distance measurement unit 106. The road width calculation unit 107 calculates the road width at the position of each intersection i by doubling the value of the shortest distance L at the position of each intersection i. The road width calculation unit 107 stores the calculated value of the road width at the position of each intersection i and information indicating the number of intersections i in the road width information storage unit 108.

[0074] The processing from the distance measurement unit 106 measuring the shortest distance L, the road width calculation unit 107 calculating the road width, to storing the calculated road width value in the road width information storage unit 108 may be configured so that processing is performed sequentially for each intersection i (i.e., a loop processing is performed), or may be configured so that processing is performed collectively for all intersections i.

[0075] When the road width information storage unit 108 stores the road width values ​​at the positions of all intersections i and information indicating the number of intersections i, the average road width calculation unit 109 reads out this information. The average road width calculation unit 109 sums up all the read road width values. Then, the average road width calculation unit 109 calculates the average road width by dividing the sum by the number of read intersections i. The average road width calculation unit 109 outputs the calculated average road width value to the average road width information output unit 110.

[0076] The average road width information output unit 110 acquires the average road width value output from the average road width calculation unit 109. The average road width information output unit 110 outputs the acquired average road width value to an external device, for example, via a network. The external device here is, for example, an interference evaluation device that performs interference evaluation using the average road width value calculated by the map data processing device 100. In this case, the average road width information output unit 110 is configured to include a communication interface that connects to the network.

[0077] Alternatively, the average road width information output unit 110 displays the acquired value of the average road width on a display unit (not shown) included in the map data processing device 100. In this case, the user refers to the value of the average road width displayed on the display unit (not shown) and inputs the value of the average road width into, for example, an external device. As described above, the external device here is, for example, an interference evaluation device that performs interference evaluation using the value of the average road width calculated by the map data processing device 100.

[0078] [Operation of map data processing device] The following describes an example of the operation of the map data processing device 100. Fig. 4 is a flowchart showing the operation of the map data processing device 100 in the first embodiment of the present invention.

[0079] The map data acquisition unit 101 acquires map information via the Internet from, for example, a server device that publishes a website that provides map information (for example, the website of the Geospatial Information Authority of Japan) (step S001). The map data acquisition unit 101 outputs the acquired map information to the road information extraction unit 102.

[0080] The road information extraction unit 102 acquires the map information output from the map data acquisition unit 101. The road information extraction unit 102 extracts road information indicating the positions of the road edge r and the road center line c of the road from the acquired map information (step S002). The road information extraction unit 102 outputs the acquired map information and the extracted road information to the evaluation target range designation unit 103.

[0081] The evaluation target range designation unit 103 acquires the map information and road information output from the road information extraction unit 102. The evaluation target range designation unit 103 also displays a map mi based on the acquired map information and road information on a display unit (not shown) provided in the map data processing device 100. While referring to the map mi displayed on the display unit (not shown), the user adjusts the size of the rectangular range that will become the evaluation target range e using an operation input unit (not shown), thereby designating the evaluation target range e (step S003). The evaluation target range designation unit 103 outputs the map information, road information, and information indicating the designated evaluation target range e to the delimiter line interval designation unit 104.

[0082] The delimiting line interval designation unit 104 acquires the map information, road information, and information indicating the evaluation target range e output from the evaluation target range designation unit 103. Furthermore, the delimiting line interval designation unit 104 causes a display unit (not shown) provided in the map data processing device 100 to display a map mi based on the acquired map information and road information, and an evaluation target range e based on the acquired information.

[0083] The user visually identifies the smallest section in the map mi displayed on the display unit (not shown) (or in the evaluation target range e), and adjusts the spacing of the delimiting lines d so that the size of the grid formed by the delimiting lines d is smaller than the size of the identified section. This divides the evaluation target range e into a grid (mesh) of the desired size (step S004). The delimiting line spacing designation unit 104 outputs map information, road information, information indicating the evaluation target range e, and information indicating the spacing of the delimiting lines d to the intersection extraction unit 105.

[0084] The intersection extraction unit 105 acquires the map information, road information, information indicating the evaluation target range e, and information indicating the intervals between the delimiter lines d, which are output from the delimiter line interval designation unit 104. Based on this acquired information, the intersection extraction unit 105 identifies the positions of all road center lines c and delimiter lines d that exist within the evaluation target range e. The intersection extraction unit 105 extracts all intersections i, which are positions where the identified road center lines c and delimiter lines d intersect (step S005). The intersection extraction unit 105 identifies the positions of all extracted intersections i. The intersection extraction unit 105 outputs the map information, road information, information indicating the evaluation target range e, and information indicating the positions of all intersections i to the distance measurement unit 106.

[0085] The distance measurement unit 106 acquires the map information, road information, information indicating the evaluation range e, and information indicating the positions of all intersections i output from the intersection extraction unit 105. The distance measurement unit 106 identifies the position where a line extending from the intersection i in a direction perpendicular to the road center line c at the position of the intersection i intersects with the road edge r. Note that there are two directions perpendicular to the road center line c, and the map data processing device 100 arbitrarily selects either direction. The distance measurement unit 106 then measures the shortest distance L between the identified position and the intersection i (step S006). The distance measurement unit 106 outputs the value of the shortest distance L at the position of each intersection i and information indicating the number of intersections i to the road width calculation unit 107.

[0086] The road width calculation unit 107 acquires the value of the shortest distance L at the position of each intersection i and information indicating the number of intersections i, which are output from the distance measurement unit 106. The road width calculation unit 107 calculates the road width at the position of each intersection i by doubling the value of the shortest distance L at the position of each intersection i (step S007). The road width calculation unit 107 stores the calculated value of the road width at the position of each intersection i and information indicating the number of intersections i in the road width information storage unit 108.

[0087] The processes of steps S006 and S007 are repeated until the road widths are calculated at all intersections i extracted in step S005 (step S008).

[0088] When the road width information storage unit 108 stores the road width values ​​at the positions of all intersections i and information indicating the number of intersections i (step S008: YES), the average road width calculation unit 109 reads out this information. The average road width calculation unit 109 sums up all the read road width values. Then, the average road width calculation unit 109 calculates the average road width by dividing the sum by the number of intersections i that have been read out (step S009). The average road width calculation unit 109 outputs the calculated average road width value to the average road width information output unit 110.

[0089] The average road width information output unit 110 acquires the value of the average road width output from the average road width calculation unit 109. The average road width information output unit 110 outputs the acquired value of the average road width, for example, via a network, to an interference evaluation device that performs interference evaluation using the value of the average road width calculated by the map data processing device 100 (step S010). This completes the operation of the map data processing device 100 shown in the flowchart of Fig. 4.

[0090] As described above, the map data processing device 100 in the first embodiment of the present invention acquires map information and accepts the specification of an evaluation range e for calculating an average road width within a map mi based on the acquired map information. The map information input to the map data processing device 100 in the first embodiment includes at least information indicating the positions of road edges r on both sides of each road and information indicating the position of a road centerline c indicating the center position of the road edges on both sides. The map data processing device 100 in the first embodiment measures the shortest distance L between the position of an intersection i at which a dividing line d dividing the evaluation range e into smaller grid-like (mesh-like) areas intersects with the road centerline c and the position of one of the road edges, and calculates the road width at the intersection i by doubling the measured value. The map data processing device 100 then calculates the average road width of the roads in the evaluation range e by calculating the average road width at each intersection i.

[0091] With this configuration, the map data processing device 100 according to the first embodiment of the present invention can calculate the average road width from the map information with higher accuracy while suppressing an increase in the amount of calculation.

[0092] As described above, the map data processing device 100 in the first embodiment of the present invention sets the size of one grid (mesh) formed by the delimiting lines d to be smaller than the size of the smallest section within the map mi (or within the evaluation range e), for example. With this configuration, the map data processing device 100 can make all road center lines c existing within the map mi (or within the evaluation range e) intersect with the delimiting lines d.

[0093] This allows the map data processing device 100 to extract all intersections i that exist within the map mi (or within the evaluation range e), including intersections i on short roads that are only as long as the length of one side of a small block, thereby enabling the average road width to be calculated with higher accuracy.

[0094] As described above, the map data processing device 100 in the first embodiment of the present invention arbitrarily selects one of the two directions perpendicular to the road center line c, measures the shortest distance to the road edge r, and calculates the average road width by considering the measured distance doubled as the road width.

[0095] By having such a configuration, the map data processing device 100 in the first embodiment can limit the number of locations for measuring road width to only the number of intersections i, and can measure the road width at the position of one intersection i in a single measurement, thereby suppressing an increase in the amount of calculation required for measurement.

[0096] Furthermore, by having such a configuration, even if information indicating the position of one road edge r is missing, the map data processing device 100 in the first embodiment can calculate the road width based on the position of the other road edge r. This allows the map data processing device 100 in the first embodiment to calculate the average road width with higher accuracy.

[0097] Generally, there is a trade-off between the accuracy of calculating the average road width and the amount of calculation. However, according to the map data processing device 100 in the first embodiment described above, the user can easily adjust the calculation accuracy and amount of calculation to the desired level by changing the size of the grid (mesh) (i.e., the interval between the delimiting lines d).

[0098] <Modification of the first embodiment> The following describes a map data processing device 100a according to a modification of the first embodiment of the present invention. Note that the description will be omitted to the extent that the configuration is similar to that of the map data processing device 100 according to the modification of the first embodiment described above, and the description will focus on the differences from the configuration of the map data processing device 100.

[0099] The basic concept of the method for calculating the average road width performed by the map data processing device 100a in the modified example of the first embodiment of the present invention will be described below.

[0100] Similar to the map data processing device 100 in the first embodiment described above, the map data processing device 100a acquires map information, receives designation of an evaluation range e for which an average road width is to be calculated from the acquired map information, and calculates the average road width of roads existing in the evaluation range e. In a modification of the first embodiment, the map information input to the map data processing device 100a includes at least information indicating the positions of road edges r on both sides of each road and a road centerline c indicating the center position of the road edges on both sides. The map data processing device 100a in the modification of the first embodiment calculates the average road width more simply based on the positions of the road edges r and the intersection points i where the road centerlines c intersect with the delimiting lines d that divide the evaluation range e into smaller grid-like (mesh-like) areas.

[0101] Here, the map data processing device 100 in the first embodiment described above and the map data processing device 100a in the modified version of the first embodiment differ in that the map data processing device 100 in the first embodiment considers the road width to be twice the distance between the position of intersection i and the position of one road edge r, whereas the map data processing device 100a in the modified version of the first embodiment measures the distance between the position of intersection i and the positions of both road edges r and calculates the road width by adding up these two distances. As a result, the map data processing device 100a in the modified version of the first embodiment requires about twice the amount of calculation to calculate the average road width compared to the map data processing device 100 in the first embodiment described above, but on the other hand, it can calculate a more accurate average road width value.

[0102] When intersections i within the evaluation range e are extracted by a method similar to that of the first embodiment, the map data processing device 100a measures the shortest distance from the position of each intersection i to the road edges r on both sides. Fig. 5 is an enlarged view of the area surrounding one of the intersections i present within the evaluation range e in Fig. 1. Fig. 5 shows road edges r on both sides of the road, a road centerline c at a position midway between the road edges r on both sides, a dividing line d, and one intersection i where the road centerline c and the dividing line d intersect.

[0103] The map data processing device 100a calculates the shortest distance L1 from the intersection i to the road edge r in one direction, and the shortest distance L2 from the intersection i to the road edge r in the other direction.

[0104] Specifically, the map data processing device 100a extends a line from the intersection point i in one of two directions perpendicular to the road centerline c at the position of the intersection point i, and identifies the position where the line intersects with the road edge r. The map data processing device 100a then measures the distance between the identified position and the intersection point i, and defines the measurement result as the shortest distance L1. Next, the map data processing device 100a extends a line from the intersection point i in the remaining direction, and identifies the position where the line intersects with the road edge r. The map data processing device 100a then measures the distance between the identified position and the intersection point i, and defines the measurement result as the shortest distance L2.

[0105] Then, the map data processing device 100a calculates the road width at the intersection point i by adding up the measured shortest distance L1 and shortest distance L2.

[0106] If the position of the road centerline c is exactly equidistant from the positions of the road edges r on both sides, the shortest distance L from intersection i to the road edge r should be the same regardless of which side of the road edge r is measured. However, on an actual map, there may be some errors in the distances between the road centerline c and each of the road edges r on both sides. Therefore, by providing a configuration that measures both the distances between the road centerline c and each of the road edges r on both sides, as in the map data processing device 100a in the modified example of the first embodiment, it becomes possible to calculate the average road width more accurately.

[0107] The map data processing device 100 in the modification of the first embodiment measures the shortest distance L1 and the shortest distance L2 for each of the positions of all intersections i that exist within the evaluation target range e, and calculates the road width by adding these two values. Therefore, for example, in the evaluation target range e of the map mi illustrated in Fig. 1, there are 36 intersections i, and therefore the map data processing device 100a performs measurement processing 72 times (=36 x 2).

[0108] The map data processing device 100a adds up all the measured road width values. Then, the map data processing device 100 calculates the average road width by dividing the added value by the number of intersections i. Therefore, in the case of the evaluation target range e of the map mi illustrated in FIG. 1, since there are 36 intersections i, the average road width value within the evaluation target range e is calculated by dividing the total value of all the measured road widths by 36.

[0109] As mentioned above, in order to make the drawing easier to see and the explanation easier to understand, it is assumed in Figure 1 that there are no narrow roads, such as back alleys. However, in reality, it is desirable to calculate the average road width taking into account the existence of narrow roads. Below, we will explain how much the amount of calculation increases when the existence of narrow roads is taken into account.

[0110] As mentioned above, the amount of calculation required to calculate the average road width is proportional to the number of intersections i. As explained above, if the partitions are identified taking into account the presence of narrow roads and the spacing between the delimiting lines d is set so that the grid size is smaller than that of the identified partitions, the number of intersections i, Ci, can be expressed by equation (1). Considering the number of back alleys for one main road in a typical urban area, the number of intersections i is estimated to be approximately 2,880 by the calculation of equation (2). Therefore, in the map data processing device 100 according to the first embodiment, the number of intersections i is estimated to be no more than 5,000 when the evaluation target range e is as shown in FIG. 1 . Therefore, in this case, the map data processing device 100 according to the first embodiment performs distance measurement processing no more than 5,000 times.

[0111] On the other hand, as described above, the calculation amount of the map data processing device 100a in the modified example of the first embodiment is about twice the calculation amount of the map data processing device 100 in the first embodiment. Therefore, when the size of the evaluation target range e is as shown in Fig. 1, the map data processing device 100a in the modified example of the first embodiment performs distance measurement processing at most 10,000 times (= 5,000 x 2).

[0112] Considering the computational capabilities of modern information processing devices, increasing the above 5,000 measurement processes to 10,000 calculation processes is not expected to lead to a significant increase in processing time. As shown in (1) above, the number of intersections i is at most on the order of the square of Nm. Therefore, the number of calculation processes is also at most on the order of the square of Nm, and considering this point, it is not expected to lead to a significant increase in processing time.

[0113] [Functional configuration of map data processing device] The functional configuration of the map data processing device 100a will be described below. Fig. 6 is a block diagram showing the functional configuration of the map data processing device 100a according to a modified example of the first embodiment of the present invention.

[0114] As shown in FIG. 6, the map data processing device 100a includes a map data acquisition unit 101, a road information extraction unit 102, an evaluation range designation unit 103, a delimiter line spacing designation unit 104, an intersection extraction unit 105, a two-way distance measurement unit 106a, a road width calculation unit 107a, a road width information storage unit 108, an average road width calculation unit 109, and an average road width information output unit 110.

[0115] The functional configuration of the map data processing device 100 in the first embodiment shown in FIG. 3 described above differs from the functional configuration of the map data processing device 100a in the modified example of the first embodiment in that a two-way distance measurement unit 106a is provided instead of the distance measurement unit 106, and a road width calculation unit 107a is provided instead of the road width calculation unit 107.

[0116] The two-way distance measurement unit 106a acquires the map information, road information, information indicating the evaluation target range e, and information indicating the positions of all intersections i output from the intersection extraction unit 105. The two-way distance measurement unit 106a identifies the positions of road edges r of all roads existing within the evaluation target range e based on the acquired map information, road information, and information indicating the evaluation target range e. For each intersection i, the two-way distance measurement unit 106a measures the shortest distance L1 between the position of the intersection i and one road edge r, and the shortest distance L2 between the position of the intersection i and the other road edge r. The two-way distance measurement unit 106a outputs the values ​​of the shortest distance L1 and the shortest distance L2 at the position of each intersection i and information indicating the number of intersections i to the road width calculation unit 107a.

[0117] Specifically, the two-way distance measurement unit 106a identifies the position where a line intersects with the road edge r when it is extended from the intersection point i in one of two directions that are perpendicular to the road center line c at the position of the intersection point i. Then, the two-way distance measurement unit 106a measures the distance between the identified position and the intersection point i, and defines the measurement result as the shortest distance L1. Next, the two-way distance measurement unit 106a identifies the position where the line intersects with the road edge r when it is extended from the intersection point i in the other direction. Then, the two-way distance measurement unit 106a measures the distance between the identified position and the intersection point i, and defines the measurement result as the shortest distance L2.

[0118] The road width calculation unit 107a acquires the values ​​of the shortest distance L1 and the shortest distance L2 at the position of each intersection i and information indicating the number of intersections i, which are output from the two-way distance measurement unit 106a. The road width calculation unit 107a calculates the road width at the position of each intersection i by adding up the value of the shortest distance L1 and the value of the shortest distance L2 at the position of each intersection i. The road width calculation unit 107a stores the calculated value of the road width at the position of each intersection i and information indicating the number of intersections i in the road width information storage unit 108.

[0119] The process in which the two-way distance measurement unit 106a measures the shortest distance L1 and the shortest distance L2, the road width calculation unit 107a calculates the road width, and the calculated road width value is stored in the road width information storage unit 108 may be configured so that the process is performed sequentially for each intersection i (i.e., a loop process is performed), or may be configured so that the process is performed collectively for all intersections i.

[0120] [Operation of map data processing device] An example of the operation of the map data processing device 100a will be described below. Fig. 7 is a flowchart showing the operation of the map data processing device 100a in the modified example of the first embodiment of the present invention.

[0121] Note that the operations from step S101 to step S105 in the flowchart shown in Fig. 7 are the same as the operations from step S001 to step S005 in the flowchart shown in Fig. 4, and therefore their explanations will be omitted. Also, the operations from step S109 to step S110 in the flowchart shown in Fig. 7 are the same as the operations from step S009 to step S010 in the flowchart shown in Fig. 4, and therefore their explanations will be omitted.

[0122] The two-way distance measurement unit 106a acquires the map information, road information, information indicating the evaluation range e, and information indicating the positions of all intersections i output from the intersection extraction unit 105. The two directions perpendicular to the road centerline c at the position of intersection i are present. The two-way distance measurement unit 106a extends a line from intersection i in one direction, and identifies the position where the line intersects with the road edge r. The two-way distance measurement unit 106a then measures the shortest distance L1 between the identified position and intersection i. Furthermore, the two-way distance measurement unit 106a extends a line from intersection i in the other direction, and identifies the position where the line intersects with the road edge r. The two-way distance measurement unit 106a then measures the shortest distance L2 between the identified position and intersection i (step S106). The two-way distance measurement unit 106a outputs the value of the shortest distance L1 and the value of the shortest distance L2 at the position of each intersection point i, and information indicating the number of intersection points i, to the road width calculation unit 107a.

[0123] The road width calculation unit 107a acquires the values ​​of the shortest distances L1 and L2 at the position of each intersection i and information indicating the number of intersections i, which are output from the two-way distance measurement unit 106a. The road width calculation unit 107a calculates the road width at the position of each intersection i by adding up the values ​​of the shortest distances L1 and L2 at the position of each intersection i (step S107). The road width calculation unit 107a stores the calculated values ​​of the road width at the position of each intersection i and information indicating the number of intersections i in the road width information storage unit 108.

[0124] The processes of steps S106 and S107 are repeated until the road widths are calculated at all of the intersections i extracted in step S105 (step S108).

[0125] As described above, the map data processing device 100a in the modified first embodiment of the present invention acquires map information and accepts the specification of an evaluation range e for calculating an average road width within a map mi based on the acquired map information. The map information input to the map data processing device 100a in the modified first embodiment includes at least information indicating the positions of road edges r on both sides of each road and information indicating the position of a road centerline c, which indicates the center of the road edges on both sides. The map data processing device 100a in the first embodiment measures the shortest distance L1 between the position of the road edge r in one direction and the shortest distance L2 between the position of the road edge r in the other direction at an intersection i, where a dividing line d dividing the evaluation range e into smaller grid-like (mesh-like) areas intersects with the road centerline c, and calculates the road width at the intersection i by adding up these measured values. The map data processing device 100a then calculates the average road width of the roads in the evaluation range e by calculating the average road width at each intersection i.

[0126] With this configuration, the map data processing device 100a according to the modification of the first embodiment of the present invention can calculate the average road width from the map information with higher accuracy while suppressing an increase in the amount of calculation.

[0127] Furthermore, as described above, the map data processing device 100a in the modified example of the first embodiment of the present invention measures the shortest distance (shortest distance L1 and shortest distance L2) to the road edge r in two directions perpendicular to the road center line c, calculates the road width by adding up the measured distances, and then calculates the average road width.

[0128] With this configuration, the map data processing device 100a in the modified example of the first embodiment can calculate the average road width with higher accuracy than the map data processing device 100 in the above-described embodiment 1. On the other hand, the map data processing device 100a in the modified example of the first embodiment limits the number of locations for measuring road width to the number of intersections i, and can measure the road width at the position of one intersection i only twice, thereby suppressing an increase in the amount of calculations involved in measurement.

[0129] Furthermore, as mentioned above, there is a trade-off between the accuracy of calculating the average road width and the amount of calculation. However, according to the map data processing device 100a in the modified example of the first embodiment described above, the user can easily adjust the calculation accuracy and amount of calculation to the desired level by changing the size of the grid (mesh) (i.e., the interval between the delimiting lines d).

[0130] <Second embodiment> The basic concept of the method for calculating the average road width performed by the map data processing device 100b according to the second embodiment of the present invention will be described below.

[0131] Similar to the map data processing device 100 in the first embodiment described above, the map data processing device 100b acquires map data, receives designation of an evaluation range e, which is a range within the acquired map data for which the average road width is to be calculated, and calculates the average road width of roads present in the evaluation range e. The map data input to the map data processing device 100b in the second embodiment includes at least information indicating whether or not each road is a road area, such as the positions of road edges r on both sides of each road, and a road centerline c indicating the center position of the road edges r on both sides.

[0132] The map data processing device 100b in the second embodiment divides the evaluation target range into smaller grid-like (mesh-like) areas and calculates the area of ​​each divided grid (hereinafter referred to as a "mesh"). Hereinafter, the area per mesh will also be referred to as a "unit area." The map data processing device 100b determines whether or not a mesh corresponds to the position of a road on the map (more precisely, whether or not the proportion of road areas within the mesh is relatively large). Hereinafter, the mesh corresponding to the position of a road on the map will also be simply referred to as the "mesh corresponding to the road."

[0133] The map data processing device 100b counts the number of meshes corresponding to roads within the evaluation target range e. The map data processing device 100b also calculates the total length of the road center lines c of all roads existing within the evaluation target range e. The map data processing device 100b then calculates the total area of ​​the meshes corresponding to the road by multiplying the unit area by the number of meshes corresponding to the road. Furthermore, the map data processing device 100b can more easily calculate the average road width by dividing the value of the total area of ​​the meshes corresponding to the road by the value of the total length of the road center lines c of the road.

[0134] That is, the map data processing device 100b in the second embodiment considers the area obtained by multiplying the number of meshes corresponding to the road by the unit area to be the area of ​​all roads existing within the evaluation target range e. Then, since the area of ​​a road is the product of the length of the road center line c and the road width, the map data processing device 100b calculates the average road width of all roads existing within the evaluation target range e by dividing the area of ​​all roads existing within the evaluation target range e by the total length of the road center lines c.

[0135] Therefore, in the calculation process of the average road width by the map data processing device 100b in the second embodiment, the size of one mesh (i.e., unit area) needs to be set so that the total area of ​​the meshes determined to be roads approximates the total area of ​​the roads on the map. In the first embodiment and the modified example of the first embodiment described above, the size of the mesh needed to be set to an appropriate size depending on the size of the divisions in the map, but in the second embodiment, the size of the mesh needs to be set to an appropriate size depending on the width of the road within the road.

[0136] FIG. 8 is a diagram showing an example of a map mi and an evaluation range e used in calculating an average road width by a map data processing device 100b according to a second embodiment of the present invention. The map data processing device 100 acquires map information from, for example, an external system via a network. FIG. 8 shows a map mi based on the above map data. As an example, the map mi shown in FIG. 8 is a map of a part of an urban area. For ease of understanding, the map mi shown in FIG. 1, which is exemplified in the first embodiment described above, and the map mi shown in FIG. 8 are of the same range.

[0137] On the map mi, lines representing roads, lines representing the outlines of structures such as buildings, lines representing paths in parks, etc. are shown by solid lines. On the map mi shown in Fig. 8, road edges r and road centerlines c are shown by solid lines. Also on the map mi, an evaluation target range e is shown by dashed lines. The evaluation target range e is specified, for example, by a user who performs interference evaluation using a user interface (operation input unit) provided in the map data processing device 100.

[0138] Furthermore, on the map mi, a plurality of delimiting lines d are indicated by dotted lines. In the second embodiment, the interval between adjacent delimiting lines d is set to be, for example, equal to or less than twice the width of the roads (particularly, the width of narrow roads) present within the map mi (or within the evaluation target range e). That is, in the second embodiment, the size of the grid formed by the delimiting lines d is determined according to the width of the roads (particularly, the width of narrow roads) included within the map mi.

[0139] Specifically, for example, a user performing interference assessment visually identifies the narrowest road among the roads included in the assessment target range e. Then, the user uses a user interface (operation input unit) provided in the map data processing device 100b to adjust the distance between adjacent delimiting lines d so that it is, for example, twice the road width of the identified road or less.

[0140] In FIG. 8, the spacing between the delimiting lines d is wider than it actually is to make the drawing easier to see and the explanation easier to understand. In FIG. 8, it is assumed that there are no narrow roads, such as back alleys, and road center lines c are not shown on narrow roads. In FIG. 8, the spacing between the delimiting lines d is set for only the wider main roads. Therefore, in order to more accurately calculate the average road width of all roads included in the evaluation range e, it is necessary to include the area surrounded by narrow roads, such as back alleys, in the evaluation range and set the spacing between the delimiting lines d narrower. The more accurate the average road width, the more accurate the interference evaluation.

[0141] Once the evaluation range e and the spacing between adjacent delimiting lines d (i.e., the size of the mesh formed by the delimiting lines d) are determined for the map mi, the map data processing device 100b calculates the area (unit area) of the mesh. The map data processing device 100b also determines whether or not each of the meshes within the evaluation range e corresponds to a road. In FIG. 8, meshes j that correspond to roads are shaded to distinguish them from meshes that are determined not to correspond to roads.

[0142] The determination of whether a mesh corresponds to a road may be made using any image recognition technology, or may be made visually by the user.

[0143] In addition, the determination of whether a mesh corresponds to a road may be made by calculating the proportion of the mesh that is occupied by roads based on information such as the position of the road edge r, and if the proportion of the mesh that is occupied by roads is above a predetermined threshold (for example, above 50%), the mesh may be determined to correspond to a road.

[0144] As mentioned above, by setting the distance between adjacent delimiting lines d to be less than twice the width of the narrow road, if a mesh is located so that it contains a narrow road, the proportion of this narrow road in the mesh is likely to be 50% or more. This increases the likelihood that such a mesh will be correctly determined to be a mesh that corresponds to a road.

[0145] As mentioned above, in order to make the drawing easier to see and the explanation easier to understand, it is assumed in Figure 1 that there are no narrow roads, such as back alleys. However, in reality, it is desirable to calculate the average road width taking into account the existence of narrow roads. Below, we will explain how much calculation is required when taking into account the existence of narrow roads.

[0146] As described above, the map data processing device 100b in the second embodiment calculates the average road width by dividing the total area of ​​the meshes corresponding to the roads within the evaluation range e by the total length of the road center lines c of the roads within the evaluation range e. That is, the map data processing device 100b calculates the average road width by performing the calculation of the following equation (3):

[0147] Average road width = (total number of meshes corresponding to roads within the evaluation range) × (unit area of ​​mesh) ÷ (total length of road center lines of roads within the evaluation range) (3)

[0148] The evaluation range e shown in FIG. 8 is divided into 14 rows and 20 columns by dividing lines d, with a total of 280 meshes (=14×20). In other words, in this case, calculations for each mesh, such as determining whether a mesh corresponds to a road, are performed 280 times. However, in FIG. 8, the spacing of the dividing lines d is set so that narrow roads such as back alleys are excluded from the evaluation, and in order to calculate a more accurate average road width, it is necessary to further narrow the spacing of the dividing lines d and make each mesh smaller.

[0149] If we consider dividing the evaluation range e into finer meshes to include narrow roads such as back alleys in the evaluation, the amount of calculation would be as follows: Let's assume that the evaluation range e is 500 meters square, and that the width of the narrow roads is approximately 3 meters. As mentioned above, it is desirable to set the spacing between delimiting lines d to no more than twice the width of the narrow roads, so for example, the spacing between delimiting lines d can be set to approximately 5 meters (≦3×2). Therefore, since the evaluation range e, which is 500 meters square, is divided by delimiting lines d spaced 5 meters apart, in this case the total number of meshes included in the evaluation range e will be approximately 10,000, as calculated by the following formula (4).

[0150] (500 ÷ 5) × (500 ÷ 5) = 10,000 (4)

[0151] Therefore, if the evaluation range e is 500 meters square, the total number of meshes will be at most 10,000, and it is estimated that the number of calculations performed on each mesh, such as determining whether a mesh corresponds to a road, will be at most 10,000. Considering the calculation capabilities of modern information processing devices, increasing the number of calculations from the several hundred times mentioned above to 10,000 will not significantly increase the processing time.

[0152] In calculating the total length of the road center lines c of roads within the evaluation range e, for straight roads, the length can be calculated at once based on the positions of both ends of the road within the evaluation range e. On the other hand, if the road is winding, the length cannot be calculated at once in this manner. In such cases, for example, the length of the road center line c can be calculated for each mesh and the calculated values ​​can be added together. In the second embodiment, since the meshes are set to be sufficiently small compared to the length of the road, even if the roads within each mesh are considered to be straight, it is unlikely that a large error will occur between the calculated length of the road center line c and the actual length of the road center line c for the entire road.

[0153] [Functional configuration of map data processing device] The functional configuration of the map data processing device 100b will be described below. Fig. 9 is a block diagram showing the functional configuration of the map data processing device 100b according to the second embodiment of the present invention.

[0154] As shown in FIG. 9, the map data processing device 100b includes a map data acquisition unit 101, a road information extraction unit 102, an evaluation range designation unit 103, a delimiter line interval designation unit 104b, a unit area calculation unit 111, a road area determination unit 112, a road area counting unit 113, a road length measurement unit 114, a road length counting unit 115, an average road width calculation unit 109b, and an average road width information output unit 110.

[0155] The configurations of the map data acquisition unit 101, road information extraction unit 102, evaluation target range designation unit 103, and average road width calculation unit 109 of the map data processing device 100b are similar to the configurations of the map data acquisition unit 101, road information extraction unit 102, evaluation target range designation unit 103, and average road width calculation unit 109, which are assigned the same reference numerals, of the map data processing device 100 in the first embodiment shown in FIG. 3 described above, and therefore description thereof will be omitted.

[0156] The delimiter line interval designation unit 104b acquires the map information, road information, and information indicating the evaluation target range e output from the evaluation target range designation unit 103. The delimiter line interval designation unit 104b also acquires information indicating the interval between delimiter lines d. The delimiter line interval designation unit 104b may also acquire information indicating the size of the grid (mesh) formed by the delimiter lines d. The delimiter line interval designation unit 104b outputs the map information, road information, information indicating the evaluation target range e, and information indicating the interval between delimiter lines d to the unit area calculation unit 111.

[0157] The delimiting line interval designation unit 104b acquires information indicating the intervals of the delimiting lines d, for example, from an external system or the like via a network. The external system referred to here is, for example, an interference evaluation device that performs interference evaluation using the average road width value calculated by the map data processing device 100b. The intervals of the delimiting lines d based on the information acquired here are, for example, intervals adjusted to be no more than twice the road width of the narrowest road within the map mi (or within the evaluation target range e).

[0158] Alternatively, the delimiting line interval designation unit 104b acquires information indicating the intervals of the delimiting lines d that is input by, for example, a user operating an operation input unit (not shown) included in the map data processing device 100b. In this case, for example, the delimiting line interval designation unit 104b causes a map mi based on the acquired map information and road information, and an evaluation target range e based on the acquired information, to be displayed on a display unit (not shown) included in the map data processing device 100b. The user performs an operation to designate the intervals of the delimiting lines d using the operation input unit (not shown) while referring to the map mi and the evaluation target range e displayed on the display unit (not shown).

[0159] Specifically, for example, the user performs an operation to adjust the spacing of the delimiting lines d on the map mi displayed on the display unit (not shown). Here, the user adjusts the spacing of the delimiting lines d so that it is no more than twice the width of the narrowest road on the map mi displayed on the display unit (not shown) (or within the evaluation target range e).

[0160] The unit area calculation unit 111 acquires the map information, road information, information indicating the evaluation target range e, and information indicating the interval between the delimiter lines d, which are output from the delimiter line interval designation unit 104b. The unit area calculation unit 111 calculates the area per mesh (unit area) based on this acquired information. The unit area calculation unit 111 outputs the map information, road information, information indicating the evaluation target range e, information indicating the interval between the delimiter lines d, and the value of the unit area to the road area determination unit 112.

[0161] The road area determination unit 112 acquires the map information, road information, information indicating the evaluation target range e, information indicating the interval between delimiting lines d, and the value of the unit area output from the unit area calculation unit 111. For all meshes included in the evaluation target range e based on the acquired information, the road area determination unit 112 determines whether or not each mesh corresponds to a road. The road area determination unit 112 outputs the map information, road information, information indicating the evaluation target range e, information indicating the interval between delimiting lines d, the value of the unit area, and information indicating the determination result for each mesh as to whether or not the mesh corresponds to a road to the road area counting unit 113.

[0162] The road area counting unit 113 acquires the map information, road information, information indicating the evaluation target range e, information indicating the interval between delimiting lines d, the unit area value, and information indicating the determination result for each mesh as to whether it corresponds to a road, which are output from the road area determination unit 112. The road area counting unit 113 counts the total number of meshes that correspond to roads within the evaluation target range e, based on the acquired determination result for each mesh as to whether it corresponds to a road. The road area counting unit 113 outputs the map information, road information, information indicating the evaluation target range e, information indicating the interval between delimiting lines d, the unit area value, and the value of the total number of meshes that correspond to roads to the road length measurement unit 114.

[0163] The road length measurement unit 114 acquires the map information, road information, information indicating the evaluation target range e, information indicating the interval between delimiting lines d, the unit area value, and the total number of meshes corresponding to the road, which are output from the road area counting unit 113. The road length measurement unit 114 measures the length of the road center line c of each road within the evaluation target range e based on the acquired map information, road information, information indicating the evaluation target range e, and information indicating the interval between delimiting lines d. The road length measurement unit 114 outputs the unit area value, the total number of meshes corresponding to the road, and the length of the road center line c for each road to the road length counting unit 115.

[0164] The road length counting unit 115 acquires the unit area value, the total number of meshes corresponding to the road, and the length of the road center line c for each road, which are output from the road length measuring unit 114. The road length counting unit 115 adds up the acquired values ​​of the lengths of the road center lines c for each road, thereby tallying up the total length of the road center lines c for all roads within the evaluation range e. The road length counting unit 115 outputs values ​​indicating the unit area value, the total number of meshes corresponding to the road, and the total length of the road center lines c to the average road width calculation unit 109b.

[0165] The average road width calculation unit 109b acquires the unit area value, the total number of meshes corresponding to the road, and the value indicating the total length of the road center lines c, which are output from the road length counting unit 115. The average road width calculation unit 109b calculates the total area of ​​the roads within the evaluation target range e by multiplying the acquired unit area value by the acquired value indicating the total number of meshes corresponding to the road. The average road width calculation unit 109b then calculates the average road width of all roads within the evaluation target range e by dividing the calculated total area value of the road by the acquired value indicating the total length of the road center lines c. The average road width calculation unit 109b outputs the calculated average road width value to the average road width information output unit 110.

[0166] [Operation of map data processing device] An example of the operation of the map data processing device 100b will be described below. Fig. 10 is a flowchart showing the operation of the map data processing device 100 in the second embodiment of the present invention.

[0167] The operations from step S201 to step S204 in the flowchart shown in FIG. 10 are the same as the operations from step S001 to step S004 in the flowchart shown in FIG. 4, and therefore a description thereof will be omitted.

[0168] The delimiting line interval designation unit 104b outputs the map information, road information, information indicating the evaluation target range e, and information indicating the interval between the delimiting lines d to the unit area calculation unit 111. The unit area calculation unit 111 acquires the map information, road information, information indicating the evaluation target range e, and information indicating the interval between the delimiting lines d output from the delimiting line interval designation unit 104b. The unit area calculation unit 111 calculates the area per mesh (unit area) based on the acquired information (step S205). The unit area calculation unit 111 outputs the map information, road information, information indicating the evaluation target range e, information indicating the interval between the delimiting lines d, and the value of the unit area to the road area determination unit 112.

[0169] The road area determination unit 112 acquires the map information, road information, information indicating the evaluation target range e, information indicating the interval between delimiting lines d, and the value of the unit area output from the unit area calculation unit 111. For all meshes included in the evaluation target range e based on the acquired information, the road area determination unit 112 determines whether or not each mesh corresponds to a road (step S206). The road area determination unit 112 outputs the map information, road information, information indicating the evaluation target range e, information indicating the interval between delimiting lines d, the value of the unit area, and information indicating the determination result for each mesh as to whether or not the mesh corresponds to a road to the road area counting unit 113.

[0170] The road area counting unit 113 acquires the map information, road information, information indicating the evaluation target range e, information indicating the interval between the delimiting lines d, the unit area value, and information indicating the determination result for each mesh as to whether it corresponds to a road, which are output from the road area determination unit 112. If the mesh corresponds to a road (step S207, Yes), the road area counting unit 113 adds 1 to the counter value (step S008), and if the mesh does not correspond to a road (step S207, No), it does not change the counter value. In this way, the number of meshes corresponding to roads is counted. When the counting of the number of meshes corresponding to roads is completed (step S209, Yes), the road area counting unit 113 outputs the map information, road information, information indicating the evaluation target range e, information indicating the interval between the delimiting lines d, the unit area value, and the value of the total number of meshes corresponding to roads to the road length measurement unit 114.

[0171] The road length measurement unit 114 acquires the map information, road information, information indicating the evaluation target range e, information indicating the interval between delimiting lines d, the unit area value, and the total number of meshes corresponding to the road, which are output from the road area counting unit 113. The road length measurement unit 114 measures the length of the road center line c of each road within the evaluation target range e based on the acquired map information, road information, information indicating the evaluation target range e, and information indicating the interval between delimiting lines d (step S210). The road length measurement unit 114 outputs the unit area value, the total number of meshes corresponding to the road, and the length of the road center line c for each road to the road length counting unit 115.

[0172] The road length counting unit 115 acquires the unit area value, the total number of meshes corresponding to the road, and the length of the road center line c for each road, which are output from the road length measuring unit 114. The road length counting unit 115 adds up the acquired length values ​​of the road center line c for each road to calculate the total length of the road center lines c for all roads within the evaluation range e (step S211). When the addition of the length values ​​for all road center lines c is completed and the total length value is obtained (step S212: Yes), the road length counting unit 115 outputs values ​​indicating the unit area value, the total number of meshes corresponding to the road, and the total length of the road center lines c to the average road width calculation unit 109b.

[0173] The average road width calculation unit 109b acquires the unit area value, the total number of meshes corresponding to the road, and the value indicating the total length of the road center lines c, which are output from the road length counting unit 115. The average road width calculation unit 109b calculates the total area of ​​the roads within the evaluation target range e by multiplying the acquired unit area value by the acquired value indicating the total number of meshes corresponding to the road. Then, the average road width calculation unit 109b calculates the average road width of all roads within the evaluation target range e by dividing the calculated total area value of the road by the acquired value indicating the total length of the road center lines c (step S213). The average road width calculation unit 109b outputs the calculated average road width value to the average road width information output unit 110.

[0174] The average road width information output unit 110 acquires the value of the average road width output from the average road width calculation unit 109b. The average road width information output unit 110 outputs the acquired value of the average road width, for example, via a network, to an interference evaluation device that performs interference evaluation using the value of the average road width calculated by the map data processing device 100b (step S214). This completes the operation of the map data processing device 100b shown in the flowchart of FIG. 10.

[0175] As described above, the map data processing device 100b in the second embodiment of the present invention acquires map information and accepts the designation of an evaluation range e for calculating an average road width within a map mi based on the acquired map information. The map information input to the map data processing device 100b in the second embodiment includes at least information indicating whether each road is a road area, such as the positions of road edges r on both sides of each road, and a road centerline c indicating the center position of the road edges r on both sides. The map data processing device 100b in the second embodiment divides the evaluation range into smaller grid-like (mesh-like) areas and calculates the area (unit area) of each divided mesh. The map data processing device 100b determines whether a mesh corresponds to a road in the map. The map data processing device 100b also counts the number of meshes that correspond to roads within the evaluation range e. The map data processing device 100b also calculates the total length of the road centerlines c of all roads present within the evaluation range e. The map data processing device 100b then calculates the total area of ​​the meshes corresponding to the road by multiplying the unit area by the number of meshes corresponding to the road. Furthermore, the map data processing device 100b calculates the average road width by dividing the value of the total area of ​​the meshes corresponding to the road by the total length of the road center line c of the road.

[0176] With this configuration, the map data processing device 100b according to the second embodiment of the present invention can calculate the average road width from the map information with higher accuracy while suppressing an increase in the amount of calculation.

[0177] As described above, in the calculation process of the average road width by the map data processing device 100b in the second embodiment, the size (unit area) of each mesh needs to be set so that the total area of ​​the meshes determined to be roads approximates the total area of ​​the roads on the map. Therefore, in the second embodiment, the size of each mesh needs to be set to an appropriate size depending on the width of the road within the road, and the distance between adjacent delimiting lines d is set to, for example, no more than twice the width of the roads (especially the width of narrow roads) that exist within the map mi (or within the evaluation target range e). With this configuration, the map data processing device 100b can calculate the average road width for all roads that exist within the map mi (or within the evaluation target range e), including narrow roads such as back alleys, and can therefore calculate the average road width with higher accuracy.

[0178] As described above, the map data processing device 100b in the second embodiment considers the area obtained by multiplying the number of meshes corresponding to the road by the unit area to be the area of ​​all roads existing within the evaluation target range e. The map data processing device 100b then calculates the average road width of all roads existing within the evaluation target range e by dividing the area of ​​all roads existing within the evaluation target range e by the total length of the road center lines c. With this configuration, the map data processing device 100b in the second embodiment can suppress an increase in the amount of calculation required to calculate the average road width.

[0179] Furthermore, as mentioned above, there is a trade-off between the accuracy of calculating the average road width and the amount of calculation. However, according to the map data processing device 100b in the second embodiment described above, the user can easily adjust the calculation accuracy and amount of calculation to the desired level by changing the size of the grid (mesh) (i.e., the interval between the delimiting lines d).

[0180] (Configuration of interference evaluation device) As described above, the map data processing device 100 in the first embodiment, the map data processing device 100a in the modified example of the first embodiment, and the map data processing device 100b in the second embodiment are devices that calculate an average road width. The calculated average road width value is output to, for example, an interference evaluation device that performs interference evaluation using the average road width value. For example, the average road width value is one of the variables in a radio wave propagation formula (hereinafter also referred to as a "propagation loss calculation formula") that the interference evaluation device uses when performing interference calculations. In other words, the interference evaluation device performs interference calculations by substituting the value of the average road width acquired from the map data processing device in each of the above-described embodiments into a variable in the radio wave propagation formula.

[0181] An interference evaluation system is configured by the map data processing device in each of the above-described embodiments and, for example, an interference evaluation device 1 described below. The interference evaluation device 1 according to one embodiment of the present invention will be described below with reference to the drawings (cited from Patent Document 1).

[0182] [Outline of interference assessment device functions] The following provides an overview of the functions of the interference evaluation device 1. FIG. 11 is a schematic diagram showing an outline of the functions of the interference evaluation device 1 according to one embodiment of the present invention.

[0183] The main function of the interference evaluation device 1 is a station DB management function that stores and manages information on a plurality of interfering stations and information on a plurality of interfered stations in a database (hereinafter referred to as "DB"). The information on the interfering station includes information indicating transmission power, frequency and bandwidth, antenna gain and filter characteristics, etc. The information on the interfered station includes information indicating frequency and bandwidth, antenna gain and filter characteristics, allowable interference power, etc.

[0184] Another main function of the interference evaluation device 1 is a propagation loss calculation function that calculates propagation loss from information on interfering stations and information on interfered stations using propagation loss calculation software or a calculation model. The propagation loss software is software that calculates propagation loss using map information. The calculation model is a model for calculating propagation loss from a propagation loss calculation formula.

[0185] Other functions of the interference evaluation device 1 include a pass / fail judgment function that determines whether or not sharing between the interfering station and the interfered station is possible based on the calculation results of the propagation loss calculation function, and a received signal strength output function that outputs information indicating the received signal strength calculated based on the calculation results of the propagation loss calculation function.

[0186] Further, another function of the interference evaluation device 1 is a GUI (Graphical User Interface) display function that displays a display screen visually showing the information used or generated by each of the above-mentioned functions. The display screen displayed by the GUI display function for allowing the user to select interfering station information and interfered station information displays desired interfering station information and interfered station information so that the user can select the desired information from the interfering station information and interfered station information stored in the DB by the station information DB management function. The propagation loss calculation function uses the selected interfering station information and interfered station information for propagation loss calculation.

[0187] 11, each display screen displayed by the GUI display function may have a guidance (advice, comment) display function that displays guidance (or advice or comments) to the user. The guidance (or advice or comments) is displayed in the form of annotations, for example.

[0188] [Functional configuration of interference evaluation device] Fig. 12 is a block diagram showing the functional configuration of an interference evaluation device 1 according to one embodiment of the present invention. As shown in Fig. 12, the interference evaluation device 1 includes a control unit 10, an input setting / selection / registration change instruction unit 11, an interference method (menu) selection unit 12, a station information input / registration unit 13, an interfered / interfered station selection unit 14, a history selection unit 15, at least one calculation condition setting unit 16, at least one calculation result display designation unit 17, an interference power calculation / pass / fail judgment unit 18, a calculation result graphic display unit 19, a storage unit 20, and an input / output unit 30.

[0189] The interference evaluation device 1 is configured to include an information processing device (for example, a general-purpose computer such as a personal computer, or a small information terminal such as a tablet terminal).

[0190] The control unit 10 controls the processing executed by each functional block of the interference evaluation device 1. The control unit 10 includes, for example, a processor such as a CPU (Central Processing Unit).

[0191] 12, the storage unit 20 includes a station DB 201, a history storage unit 202, and a map information DB 203. The storage unit 20 is configured to include, for example, a storage medium such as a magnetic disk or a semiconductor memory, or a combination of these storage media.

[0192] 12, the input / output unit 30 includes an operation input unit 301 and a display unit 302. The operation input unit 301 includes an input member (e.g., a keyboard, a mouse, etc.) that accepts operation inputs from a user. The display unit 302 includes an output member (e.g., a liquid crystal display, etc.) that displays a display screen presented to the user. The operation input unit 301 and the display unit 302 may be configured as a single member (e.g., a touch panel, etc.) that has input / output functions.

[0193] The input setting / selection / registration change instruction unit 11, the interference method (menu) selection unit 12, the station information input / registration unit 13, the interfered / interfered station selection unit 14, the history selection unit 15, at least one calculation condition setting unit 16, at least one calculation result display designation unit 17, the interference power calculation / pass / fail judgment unit 18, and the calculation result graphic display unit 19 may be functions implemented by a software program executed by the control unit 10. In this case, for example, this software program is stored in the storage unit 20, and is read and executed by the control unit 10.

[0194] The input setting / selection / registration change instruction unit 11 acquires information input from the operation input unit 301 by user operation input. The input setting / selection / registration change instruction unit 11 converts the information into instructions indicating input setting / selection / registration change, etc. that can be recognized by each functional block of the interference assessment device 1, and outputs the instructions to each functional block. Specifically, the input setting / selection / registration change instruction unit 11 converts, for example, an electrical signal input from the operation input unit 301 into input data that is input to a software program that constitutes each functional block of the interference assessment device 1.

[0195] The map information DB 203 is a database that stores map information. The map information here refers to, for example, information indicating the altitude for each position (e.g., latitude and longitude) and the objects present (e.g., buildings, roads, rivers, etc.). The map information DB 203 is used to display, on a map, the positions of wireless stations that are the subject of interference evaluation, the interference evaluation results, etc.

[0196] The map data processing device in each of the above-described embodiments may acquire map information from the map information DB 203. In this case, the map indicated by the map information needs to include at least information necessary to identify the positions of the road edge r and road center line c of the above-described road.

[0197] The calculation result display specification unit 17 specifies how the calculation results of interference evaluation, etc. are to be displayed on the map displayed on the display unit 302, based on instruction information input from the operation input unit 301, which indicates instructions from the user.

[0198] The calculation result diagram display unit 19 displays the evaluation results of the interference evaluation on a map displayed on the display unit 302 based on the designation by the calculation result display designation unit 17 .

[0199] The history storage unit 202 accumulates information (hereinafter also referred to as "history information") indicating calculation conditions and evaluation results when evaluating interference with wireless stations that were previously the subject of interference evaluation. The history information stored in the history storage unit 202 is used in new interference evaluations.

[0200] The history selection unit 15 specifies how to select and utilize the history information accumulated in the history storage unit 202 based on instruction information input from the operation input unit 301, which indicates instructions from the user.

[0201] The station DB 201 (station information storage unit) is a database containing information about wireless stations that are the subject of interference evaluation.

[0202] The interfered / interfered station selection unit 14 (station information selection unit) selects information about wireless stations stored in the station DB 201 based on instruction information input from the operation input unit 301, which indicates instructions from the user, and uses the information for interference evaluation.

[0203] The station information input / registration unit 13 inputs and registers information about wireless stations into the station DB 201 based on instruction information input from the operation input unit 301, which indicates an instruction from the user.

[0204] The interference method (menu) selection unit 12 determines what type of interference evaluation is to be performed based on instruction information input from the operation input unit 301, which indicates an instruction from the user.

[0205] The calculation condition setting unit 16 sets calculation conditions for interference evaluation in the interference method selected by the interference method (menu) selection unit 12. The calculation condition setting unit 16 can set calculation conditions for interference evaluation using information about the wireless station selected by the interfered / interfered station selection unit 14.

[0206] The selection of the information on the wireless stations and the setting of the calculation conditions for interference evaluation are performed via the input setting, selection and registration change instruction unit 11.

[0207] The interference power calculation and pass / fail judgment unit 18 calculates the interference power and judges whether it is a pass or a fail. After the calculation condition setting unit 16 selects information about the radio station to be evaluated and sets the calculation conditions for interference evaluation, when an instruction to execute calculation is given to the interference power calculation and pass / fail judgment unit 18 via the input setting, selection, and registration change instruction unit 11, the interference power calculation and pass / fail judgment unit 18 executes the calculation of the interference power. The interference power calculation and pass / fail judgment unit 18 compares the value of the interference power based on the result of the calculation of the interference power with the allowable value of interference and judges whether it is a pass or a fail. The pass / fail judgment here is a judgment as to whether the interfering station, which is the radio station to be evaluated, and the interfered station, which is affected by the interfering station, can share the same area.

[0208] The calculation result display designation unit 17 stores information indicating the calculation results of interference evaluation output from the interference power calculation / pass / fail judgment unit 18 in the history storage unit 202, or displays the information on the map displayed on the display unit 302, as described above.

[0209] As described above, there may be a plurality of calculation condition setting units 16 and a plurality of calculation result display designation units 17. In this case, the functions of the plurality of calculation condition setting units 16 and the plurality of calculation result display designation units 17 are partially different from one another. The plurality of calculation condition setting units 16 and the plurality of calculation result display designation units 17 are selected and used according to the type of interference evaluation based on instruction information input from the operation input unit 301, which indicates an instruction from the user.

[0210] Below, we will explain the relationship between the outline of the functions of the interference evaluation device 1 described with reference to Figure 11 (hereinafter simply referred to as the "functional outline") and the functional configuration of the interference evaluation device 1 described with reference to Figure 12 (hereinafter simply referred to as the "functional configuration").

[0211] In the above-mentioned functional overview, the station DB management function that stores and manages information on multiple interfering stations and information on multiple interfered stations in a DB corresponds to the station information input / registration unit 13 and the interfering / interfered station selection unit 14 in the above-mentioned functional configuration.

[0212] In addition, the propagation loss calculation function in the above-mentioned functional overview, which calculates propagation loss from information on an interfering station and information on an interfered station using propagation loss calculation software or a calculation model, corresponds to at least one calculation condition setting unit 16 and a part of the interference power calculation / pass / fail judgment unit 18 in the above-mentioned functional configuration.

[0213] The average road width value calculated by the map data processing device in each of the above-described embodiments is used, for example, in a propagation loss calculation function that calculates propagation loss from information on interfering stations and information on interfered stations, which is realized by propagation loss calculation software or a calculation model. That is, the average road width value calculated by the map data processing device is used, for example, in the calculation condition setting unit 16 and the interference power calculation / pass / fail judgment unit 18.

[0214] In addition, the pass / fail judgment function in the above-mentioned functional overview (which judges whether or not sharing between the interfering station and the interfered station is possible based on the calculation results by the propagation loss calculation function) corresponds to part of the interference power calculation / pass / fail judgment unit 18 and the result display function by the calculation result display designation unit 17 in the above-mentioned functional configuration.

[0215] In addition, the received signal strength output function (which outputs information indicating the received signal strength calculated based on the calculation result by the propagation loss calculation function) in the above-mentioned functional overview corresponds to part of the interference power calculation / pass / fail judgment unit 18 and the result display function by the calculation result display designation unit 17 in the above-mentioned functional configuration.

[0216] Hereinafter, the details of each function of the interference evaluation device 1 will be described with reference to the above-mentioned example screen of the display screen generated by the GUI display function of the interference evaluation device 1.

[0217] [Main menu screen] The main menu screen displayed on the display unit 302 will now be described. 13 is a schematic diagram showing an example of a main menu screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. As shown in the figure, the main menu screen m displays four menus: "Interference study," "Intermodulation study," "Simple station placement study," and "Management tool." Each menu includes a submenu.

[0218] The main menu screen m is generated by the interferometry (menu) selection unit 12 and displayed by the display unit 302. The interferometry (menu) selection unit 12 also controls the display of the main menu screen m by the display unit 302 based on information input by the operation input unit 301.

[0219] As shown in Figure 13, the submenus belonging to the "Interference Study" menu include "Map" and "Model," the submenu belonging to the "Simple Station Placement Study" menu includes "Simple Station Placement Study," the submenu belonging to the "Intermodulation Study" menu includes "Selection Prohibited Frequency Calculation" and "Interference Wave Level Study," and the submenu belonging to the "Management Tools" menu includes "Station DB Management."

[0220] Each submenu is a selection button, and when one of the submenus is selected based on the user's operation input via the operation input unit 301 (i.e., when the selection button is pressed), the interference evaluation device 1 starts various processes.

[0221] In the main menu screen m shown in Fig. 13, the submenus belonging to the menus "Interference study," "Simple station placement study," and "Intermodulation study" are submenus that the user selects when performing interference assessment. These submenus are provided to allow the user to select the interference calculation method to be used for interference assessment (i.e., to allow the user to select the type of interference assessment to be used).

[0222] 13, a submenu ("Station DB Management") belonging to the "Management Tools" menu is a submenu that is selected when the user wants to manage settings and information related to the interference evaluation device 1.

[0223] On the main menu screen m shown in Figure 13, when a selection button corresponding to one of the submenus included in the menus "Interference Study," "Simple Station Placement Study," and "Intermodulation Study" is pressed, the screen transitions from this main menu screen m to an interference calculation condition setting screen for performing interference evaluation corresponding to the selected submenu.

[0224] Below, we will explain the functions of each menu included in the main menu screen m shown in Fig. 13. Fig. 14 is a function list for explaining the functions of each menu displayed on the main menu screen generated by the interference evaluation device 1 according to one embodiment of the present invention.

[0225] "Map," a submenu belonging to the "Interference Consideration" menu, is a submenu selected by the user when performing interference assessment (hereinafter referred to as "map-based interference assessment"), which is performed by specifying at least one of the specific location of the interfering station or interference source that causes interference and the specific location of the interfered station that is affected by the interference, in the interference calculation condition settings.

[0226] In addition, as will be described in more detail later, in map-based interference assessment, the interference assessment results, the locations of the interfering and interfered stations on the map, and topographical information between the interfering and interfered stations are also shown in the profile diagram.

[0227] Although not shown in the function list in Fig. 14, the types of map-based interference assessment are further subdivided. Details will be described later, but interference calculations for map-based interference assessment include "point calculation," "area calculation," and "satellite and ground station calculation."

[0228] In addition, for each type of interference calculation, such as the multiple types of interference calculation included in the map-based interference calculation (i.e., "point calculation," "area calculation," and "satellite and ground station calculation") and the model-based interference calculation, a calculation condition setting unit 16 and a calculation result display specification unit 17 are provided (as shown in FIG. 12).

[0229] Point calculation is an evaluation calculation used when the positions of both the interfering station and the interfered station are identified. In map-based interference evaluation using point calculation, the interference occurring between the interfering station and the interfered station is calculated based on the identified positions of the interfering station and the interfered station. This results in a pass / fail judgment as to whether the interference is tolerable. In addition, the difference between the allowable amount of interference that the interfered station can tolerate and the amount of interference that occurs when the interfered station is affected by the interference is calculated.

[0230] Area calculation is an evaluation calculation used when either the location of the interfering station or the location of the interfered station is specified. In map-based interference evaluation using area calculation, the location of the identified interfering station or interfered station is used as a reference, and the area around that location is divided into a grid (mesh) on the map. Then, when an interfering station or interfered station whose location is not specified is placed on the mesh, the amount of interference between the interfering station and the interfered station is calculated. This shows on the map the range where the interference effect occurs and the range where interference is tolerable.

[0231] Satellite and ground station calculations are used when the location of the ground station is known. Map-based interference assessments using satellite and ground station calculations determine whether or not there is an interference effect from a satellite, whether it is geostationary or orbiting. If there is an interference effect from a satellite, it determines whether or not that effect is acceptable. Conversely, it also determines whether or not interference from a ground station (whose location is known) will affect a satellite.

[0232] "Model," a submenu belonging to the "Interference Study" menu, is a submenu selected by the user when "interference assessment is performed by specifying model-like conditions in the condition settings for interference calculation when the positions of the interfering station and the interfered station are ambiguous (or unknown) (hereinafter referred to as "model-based interference assessment"). The model-like conditions are specified conditions based on, for example, the distance between the interfering station and the interfered station, and the relative antenna direction angles of the interfering station and the interfered station.

[0233] Model-based interference assessment requires an index that indicates how much distance (i.e., how much separation) is required between the interfering station and the interfered station to avoid being affected by interference, regardless of the geographical environment in which each wireless station is installed.

[0234] "Simple Station Placement Study", a submenu belonging to the "Simple Station Placement Study" menu, is a submenu selected by the user when "when the position of either the interfering station or the interfered station is specified, an interference assessment is performed by calculating areas affected by interference (where the interfering station and the interfered station cannot share) and areas not affected by interference (where the interfering station and the interfered station can share)." In the interference assessment using simple station placement study, the calculation results showing the interference level are displayed as a heat map on a map.

[0235] As mentioned above, the submenus under the "Intermodulation Study" menu include "Prohibited Frequency Selection" and "Interference Level Study." Intermodulation study is a study of the phenomenon (third harmonic) in which interference waves of two different frequencies, f1 and f2, affect another frequency, f3 (=2f1±f2). We will not explain the contents of "Prohibited Frequency Calculation" and "Interference Level Study" used in this intermodulation study.

[0236] As shown in the main menu screen shown in FIG. 13 and the function list shown in FIG. 14, the interference assessment device 1 allows the user to easily select a desired method from among a plurality of interference assessment methods, and interference calculations are performed according to the selected method to perform interference assessment.

[0237] "Station DB Management," a submenu belonging to the "Management Tools" menu, is a submenu selected by the user when "managing (e.g., adding, editing, or using in interference calculations) station information of interfering and interfered stations that are the subject of interference evaluation in the station DB."

[0238] [Station DB management] The following describes the station DB management screen displayed on the display unit 302. Fig. 15 is a schematic diagram showing an example of the station DB management screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. The station DB management screen sm shown in Fig. 15 is a setting screen for managing station information of wireless stations that are interfering stations and interfered stations.

[0239] The station DB management screen sm is generated by the station information input / registration unit 13 and displayed by the display unit 302. The station information input / registration unit 13 controls the display of the station DB management screen sm by the display unit 302 based on information input by the operation input unit 301.

[0240] As shown in FIG. 15, the station DB management screen sm has an "Add" button for registering new station information in the station DB 201, an "Edit" button for modifying the contents of station information already stored in the station DB 201, and a "Delete" button for deleting station information stored in the station DB 201.

[0241] 15, a list of station information is displayed at the bottom of the station DB management screen sm. The station information displayed in this list is station information that matches the filtering conditions based on items such as "frequency band" and "station name" displayed in the "filtering conditions" column at the top of the station DB management screen sm. When at least one piece of station information is selected from the station information displayed in this list of station information, the "edit" button or the "delete" button is pressed to modify or delete the station information stored in the station DB 201.

[0242] For example, when "2 GHz" is selected in the "Frequency Band" pull-down menu on the station DB management screen sm shown in Fig. 15 and the "Display" button is pressed, a list of system names is displayed in the "System Name" field. In Fig. 15, "System_21," "System_22," "System_23," "System_24," and "System_25" are displayed.

[0243] Here, when the "Display" button is pressed with the two checkboxes "System_24" and "System_23" selected, a list of station information for wireless stations corresponding to either "System_24" or "System_23" is displayed at the bottom of the station DB management screen sm. As shown in Fig. 15, the list of station information displays the "station name" of each wireless station, information indicating the location where each wireless station is installed ("latitude" and "longitude"), information indicating the location of the wireless station opposite each wireless station ("latitude 2" and "longitude 2"), the "system name" used by each wireless station, the "center frequency" for wireless communication using this system, etc.

[0244] Narrowing down candidate wireless stations for interference assessment based on these "frequency bands" and "center frequencies" is important in interference assessment because interference in wireless systems occurs between systems that use the same frequency band or systems with similar center frequencies.

[0245] 15, four wireless stations (station "1," station "2," station "3," and station "4") are listed in a list of station information. For example, the top row of the list of station information displays station information in which the station name is "Station 2," the location of this wireless station is at latitude "35.65XX" and longitude "139.89XX," the location of the opposing wireless station is at latitude "35.73XX" and longitude "139.94XX," the system name is "System_23," and the center frequency is "2.24XX MHz." For example, the fourth row (bottom row) of the station information list displays station information in which the station name is "Station 1," the location of this wireless station is at latitude "35.39XX" and longitude "139.58XX," the location of the opposing wireless station is at latitude "35.52XX" and longitude "139.91XX," the system name is "System_24," and the center frequency is "2.24XXMHz."

[0246] 15, the station information in the third row of the station information list is highlighted (highlighted). This highlighting indicates that specific station information has been selected in the station information list. In this way, when a specific station is selected from the station information list, pressing the "Add" button, "Modify" button, or "Delete" button located at the bottom of the station DB management screen adds new station information, modifies the station information stored in the station DB 201, or deletes the station information stored in the station DB 201.

[0247] In this way, the station DB management screen sm shown in FIG. 15 can be used to manage the station DB 201 that stores station information of wireless stations (interfering station information and interfered station information) used in interference calculation.

[0248] The following describes the station DB editing screen displayed on the display unit 302. Fig. 16 is a schematic diagram showing an example of the station DB editing screen displayed by the interference evaluation device 1 according to an embodiment of the present invention. The station DB editing screen se shown in Fig. 16 is a setting screen for editing station information stored in the station DB 201.

[0249] The station DB editing screen se is generated by the station information input / registration unit 13 and displayed by the display unit 302. The station information input / registration unit 13 controls the display of the station DB editing screen se by the display unit 302 based on information input by the operation input unit 301.

[0250] 16, at the top of the station DB editing screen se, there are arranged radio buttons for selecting one of the items "Terrestrial Station," "Satellite," and "Other than Communication System." Depending on which of these radio buttons is selected, the items displayed at the bottom of the station DB editing screen se will differ.

[0251] In the station DB editing screen se shown in Fig. 16, the "Ground Station" radio button is selected. Therefore, for example, setting items such as "Orbital Altitude" required for "Satellite" are hidden. For example, if the "Other than Communication System" radio button is selected, setting items related to "Antenna Specifications" are hidden.

[0252] As shown in Fig. 16, the station information items set on the station DB editing screen se can be categorized into "station name," "location (latitude and longitude)," "system specifications," and "antenna specifications." The setting items that belong to the system specifications include "frequency band," "system name," "filter characteristics," "device type," "polarization," "transmission power," "transmission bandwidth," and "required I / N to avoid interference."

[0253] The "frequency band" indicates the frequency band used for wireless communication. The value of this "frequency band" is an important parameter when narrowing down the candidates for wireless stations to be subjected to interference evaluation.

[0254] 16, the station DB editing screen se does not display a setting item for setting the "center frequency," but it may be displayed. This "center frequency," like the "frequency band," is also an important parameter when determining whether or not to include a wireless station as a target in interference assessment. For example, if the center frequencies of an interfering station and an interfered station are the same or similar, the interfering station and the interfered station are subject to interference assessment, whereas if the center frequencies are significantly different, the interfering station and the interfered station are not subject to interference assessment.

[0255] "System name" indicates the name of the wireless system used for communication. "Filter characteristics" indicates the characteristics of the filter according to the frequency band. "Device type" indicates the type of wireless device in the wireless system. In the "Polarization" setting item, "Vertical polarization (V polarization)", "Horizontal polarization (H polarization)", or (for example, for satellites) "Circular polarization" is selected from the pull-down menu. "Transmission power" indicates the power transmitted as radio waves from the wireless transmitter to the antenna.

[0256] "Transmission bandwidth" refers to the range of frequencies occupied by the modulation of the carrier wave. The transmission bandwidth is also called "occupied bandwidth" or simply "bandwidth." The transmission bandwidth is calculated based on the difference between the highest and lowest frequencies used in wireless transmission. "Required I / N to be subjected to interference" is an index value that serves as a criterion for determining the allowable interference power. Specifically, the sum of the system noise NS [dBm] and the required I / N to be subjected to interference [dBm] (NS + required I / N to be subjected to interference [dBm]) is the allowable interference power.

[0257] As shown in FIG. 16, the "antenna specifications" setting items include setting items for the transmitting side and setting items for the receiving side. In many cases, wireless stations used for communication share a transmitting antenna and a receiving antenna. Therefore, the parameter values ​​for both the transmitting side and the receiving side are often the same. However, to accommodate cases where the transmitting antenna and the receiving antenna are configured as separate antennas, the station DB editing screen se shown in FIG. 16 is configured so that antenna specifications can be set separately for the transmitting side and the receiving side.

[0258] As shown in FIG. 16, the setting items for "antenna specifications" include (for both transmission and reception) "antenna name," "antenna gain," "antenna azimuth," "antenna height above ground," and "antenna elevation angle."

[0259] The antenna name indicates the antenna installed at the radio station. "Antenna gain" indicates the gain that the antenna exerts on the transmission power, including the directivity of the antenna pattern. "Antenna azimuth" indicates the horizontal direction in which the antenna is facing. In general wireless communications, the associated opposite station is often located in the direction indicated by this "antenna azimuth." "Antenna height above ground" indicates the height of the installed antenna from the ground. When interference assessment is performed taking into account the terrain, the value obtained by adding the altitude to this "antenna height above ground" is used in the interference calculation. "Antenna elevation" indicates the vertical direction of the antenna.

[0260] As shown in FIG. 16, the "opposite station" setting item is configured to be selectable using a pull-down menu. Therefore, a desired wireless station can be selected from among the wireless station candidates displayed in the pull-down menu among the wireless stations stored in the station DB 201. Alternatively, if the number of wireless stations stored in the DB is large, the stations narrowed down and listed on the station DB management screen se in FIG. 15 may be displayed in a pull-down menu for selection. After the "opposite station" is selected, pressing the "← (left arrow)" button displayed to the left of the "opposite station" item automatically calculates the antenna azimuth angle from the position (latitude, longitude) of the wireless station and the position (latitude, longitude) of the selected opposite station, and the calculated value can be automatically set. The antenna azimuth angle is, for example, an angle measured clockwise from north, which is 0 degrees.

[0261] In this way, after the "opposite station" is selected from the pull-down menu, the function of setting the antenna azimuth angle using the "← (left arrow)" button is provided for each of the transmitting antenna and the receiving antenna. For example, in the case of a relay station, the antenna azimuth angle of the transmitting antenna and the antenna azimuth angle of the receiving antenna may each point in the direction of a different opposite station.

[0262] In addition, by registering or modifying the values ​​of each of the above setting items and pressing the "Save" button located at the bottom of the station DB editing screen se, new station information is added to the station DB 201 or station information already stored in the station DB 201 is modified.

[0263] As described above, in the interference evaluation device 1, the antenna direction is automatically calculated and set from the opposite station, so that more accurate values ​​can be easily obtained in interference evaluation that takes into account the attenuation of antenna pattern characteristics.

[0264] The following describes screen transitions on the display screen in station DB management: Fig. 17 is a diagram for explaining screen transitions on the display screen displayed by the interference evaluation device 1 according to one embodiment of the present invention.

[0265] As shown in Fig. 17, the main menu screen transitions to a station DB management screen. Furthermore, the station DB management screen transitions to a station DB editing screen. Note that the main menu screen referred to here is, for example, the main menu screen m shown in Fig. 13, the station DB management screen referred to here is, for example, the station DB management screen sm shown in Fig. 15, and the station DB editing screen referred to here is, for example, the station DB editing screen se shown in Fig. 16.

[0266] The station information managed and edited via these display screens is selectively used when setting the interfering station and the interfered station on the calculation condition setting screen described later. This eliminates the need for the user to examine the details of the interfering station and the interfered station when performing interference evaluation, and allows the user to select desired station information from the station information stored in the station DB 201. This makes interference evaluation easier.

[0267] [Map-based interference assessment] The map-based interference evaluation will be described below. Fig. 18 is a schematic diagram showing an example of an execution condition specification screen for map-based interference evaluation displayed by the interference evaluation device 1 according to one embodiment of the present invention.

[0268] 18 is generated by the calculation condition setting unit 16 and displayed by the display unit 302. The calculation condition setting unit 16 controls the display of the execution condition setting screen h1 by the display unit 302 based on information input by the operation input unit 301.

[0269] As shown in Fig. 18, an item for specifying the "calculation method" is displayed at the top of the execution condition specification screen h1. In Fig. 18, in the item for specifying the "calculation method," "point calculation" is selected by checking the radio button for "point calculation."

[0270] In this way, when "Point Calculation" is selected in the item for specifying the "Calculation Method," the execution condition specification screen h1 becomes a screen as shown in Fig. 18. That is, the execution condition specification screen h1 is a screen for specifying the execution conditions for calculating interference between an interfering station and an interfered station when the positions of the interfering station and the interfered station are known in advance.

[0271] 18, an "Interfering station selection" button and an "Interfered station selection" button are arranged on the execution condition specification screen h1. By pressing the "Interfering station selection" button and the "Interfered station selection" button, the station information of a wireless station to be set as an interfering station and the station information of a wireless station to be set as an interfered station can be selected from the station information stored in the station DB 201, and the selected station information can be specified as the execution condition for the interference calculation.

[0272] When the "Select Interfering Station" button and the "Select Interfered Station" button are pressed and the station information of the interfering station and the interfered station is specified, a list of the specified station information that is read out from the station DB 201 is displayed in the list display area of ​​"Interfered / Interfered Information" displayed in the middle of the execution condition specification screen h1. As shown in Fig. 18, the list displayed in the list display area of ​​"Interfered / Interfered Information" includes the items "Interfered / Interfered", "Station Name", "Latitude 1", "Longitude 1", "Latitude 2", "Longitude 2", "System Name", and "Antenna Name".

[0273] The "Interfering / Interfered" field displays information indicating whether the selected wireless station is an interfering station or an interfered station (i.e., a value of either "interfering" or "interfered"). The "Station Name" field displays the name of the selected interfering station or interfered station. The "Latitude 1" and "Longitude 1" fields display the latitude and longitude, respectively, of the location where the selected interfering station or interfered station is installed.

[0274] The "Latitude 2" and "Longitude 2" fields show the latitude and longitude of the location where the opposite station facing the selected interfering station or interfered station is installed. The "System Name" field shows the name of the wireless system used by the selected interfering station or interfered station. The "Antenna Name" field shows the name of the antenna used by the selected interfering station or interfered station.

[0275] On the execution condition specification screen h1 shown in Fig. 18, the station information of the four selected wireless stations is displayed in the list displayed in the list display area for "Interference / Interference Information." As shown in the figure, the station information displayed at the top of the list is "Interference / Interference," and the information displayed in the items "Interference / Interference," "Station Name," "Latitude 1," "Longitude 1," "System Name," and "Antenna Name" is "Interference," "Station 2," "35.65X," "139.84X," "System_52," and "B," respectively.

[0276] This indicates that the radio station shown in the station information displayed at the top of the list is the radio station selected as the "interfering station," has the name "Station 2," is installed at a location with latitude and longitude of "35.65X" and "139.84X," is the name of the radio system being used is "System_52," and is the name of the antenna being used is "B."

[0277] 18 is temporarily saved and later registered in the history saving unit 202. This temporary saving and registration in the history saving unit 202 is performed by pressing the "temporarily save" button located at the bottom of the execution condition specifying screen h1.

[0278] Furthermore, by pressing the "History Selection" button on the upper right side of the execution condition specification screen h1, information indicating the execution conditions specified in past interference calculations can be read from the history storage unit 202. This makes it possible to specify execution conditions by reusing the execution conditions specified in past interference calculations from the history information stored in the history storage unit 202. When the "History Selection" button is pressed, the screen transitions to the history selection screen h2, for example, as shown in FIG. 19.

[0279] Fig. 19 is a schematic diagram showing an example of a history selection screen for map-based interference evaluation displayed by the interference evaluation device 1 according to one embodiment of the present invention. On the history selection screen h2 shown in Fig. 19, history information stored in the history storage unit 202 is read out and displayed. Furthermore, on the history selection screen h2, desired execution conditions specified in past interference calculations are selected from the displayed history information and reused as the execution conditions for the interference calculation.

[0280] 19 is generated by the history selection unit 15 and displayed by the display unit 302. The history selection unit 15 controls the display of the history selection screen h2 by the display unit 302 based on information input by the operation input unit 301.

[0281] As shown in Fig. 19, a display field for "History Folder List" is displayed on the left side of the history selection screen h2, and a display field for "Calculation Conditions" is displayed on the right side. The display field for "History Folder List" displays a list of folder names such as "20171108100502_Point Calculation" and "20171108100831_Model Calculation". The folder names included in this list are the folder names of folders (history folders) in which history information is stored in the history storage unit 202.

[0282] For example, as shown in Fig. 19, when "20171121091351_area calculation" is selected from the list displayed in the display field of the "history folder list," the history information stored in the selected history folder is displayed in the display field of the "calculation conditions." The display field of the "calculation conditions" on the history selection screen h2 illustrated in Fig. 19 displays, for example, information about the interfering station and the interfered station, and information indicating the calculation conditions. The information about the interfering station and the interfered station includes, for example, the station name, installation location (latitude and longitude), system name, device type, etc.

[0283] Furthermore, in the display field for "History Folder List" on the history selection screen h2 illustrated in Fig. 19, the history folder for "Area Calculation" is selected, and therefore information about "Area Designation" is displayed in the display field for "Calculation Conditions." This information about "Area Designation" includes information indicating the range of the area where the area calculation is performed (i.e., the latitude and longitude of the top left point and bottom right point (on a map with north at the top) of the area where the area calculation is performed).

[0284] Furthermore, the "Calculation Conditions" display field on the history selection screen h2 shown in FIG. 19 displays information indicating the antenna direction of the interfering station, information indicating the calculation level, and the like. Here, the "worst" antenna direction refers to the antenna being pointed in the direction of the interfered station. In addition, the antenna direction may be specified to be offset by a certain angle from the interfered station, or a specific direction in which the interfering antenna is located. Furthermore, the calculation level may take into account attenuation due to terrain and buildings in addition to the "worst (free space loss calculation)."

[0285] In this way, on the history selection screen h2, it is possible to display details of the history information (such as the execution conditions for interference calculations) stored in each history folder included in the list displayed in the display field for the "History Folder List." This allows the user to select history information while checking the details of each piece of history information on the history selection screen h2.

[0286] That is, the history selection screen h2 has a mechanism that allows the user to select history information while simultaneously checking both the interference assessment method (for example, point calculation, area calculation, model calculation, etc.) based on each piece of history information and the execution conditions for the interference calculation (for example, station name, type, location, system name, etc.). This mechanism makes it possible to select more appropriate history information for the interference assessment that will be performed.

[0287] The name of the history folder ("history folder name") selected from the list displayed in the "history folder list" display field is also displayed in the "calculation conditions" display field on the history selection screen h2 illustrated in Fig. 19. This allows the user to check the information indicating the interference assessment method and the information indicating the execution conditions for interference calculation, which are included in the selected history information, simply by referring to the "calculation conditions" display field.

[0288] When a history folder is selected from the list displayed in the "History Folder List" display field, the "Select" button located at the bottom of the history selection screen h2 switches from disabled to enabled. When this "Select" button is pressed, the execution conditions for the interference calculation based on the history information are set in the execution condition specification screen h1 shown in Figure 18.

[0289] Specifically, for example, in the case of the history selection screen h2 illustrated in Fig. 19, the history information stored in the selected history folder of "20171121091351_area calculation" includes the calculation method for interference assessment ("point calculation") shown in Fig. 18, the interfered station and interfered station that are the subject of the interference calculation execution condition specification, as well as information indicating the calculation level specification (information specifying each of "consideration of attenuation due to terrain," "consideration of attenuation due to buildings," and "consideration of additional losses"). This allows the user to set all setting items that need to be set as the execution conditions for the interference calculation simply by selecting a history folder from the list of history folders.

[0290] The station selection screen for selecting an interfering station and an interfered station, which are set as execution conditions for interference calculation, will be described below. Fig. 20 is a schematic diagram showing an example of a station selection screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. The station selection screen ss shown in Fig. 20 is a screen that is displayed when the "Select interfering station" button or the "Select interfered station" button is pressed on the execution condition specification screen h1 shown in Fig. 18.

[0291] The station selection screen ss is generated by the station information input / registration unit 13 and displayed by the display unit 302. The station information input / registration unit 13 also controls the display of the station selection screen ss by the display unit 302 based on information input by the operation input unit 301.

[0292] As shown in Figure 20, a pull-down menu for selecting "Frequency Band" is located in the "Filtering Conditions" display area displayed in the upper section of the station selection screen ss. Also, below the "Frequency Band" display area is a "System Name" display area, displaying a list of system names. When the frequency band used by the wireless station is selected using the pull-down menu, the system names displayed in the list are narrowed down.

[0293] For example, the station selection screen s shown in Fig. 20 shows a state in which the 5 GHz frequency band has been selected using a pull-down menu. As a result, only the system names of wireless systems using the 5 GHz band are displayed in the "System Name" list. Note that it is generally important to narrow down the candidates for wireless stations to be subject to interference calculation by frequency band. This is because interference effects can occur even between different wireless systems if they use the same frequency band.

[0294] If the wireless systems are the same, interference will occur. When the user wants to evaluate interference between the same wireless systems, he or she selects the same wireless system from the "System Name" list and presses the "Display" button. When the "Display" button is pressed, a list of wireless stations is displayed in the display area at the bottom of the station selection screen ss, as shown in Figure 20. From the displayed list, the user can select the wireless station to be the target of interference evaluation.

[0295] Furthermore, the candidate wireless stations to be subjected to interference calculation can be narrowed down by "equipment type" (for example, relay station, base station, or terminal station). On the station selection screen s shown in FIG. 20, the "equipment type" can be selected using a pull-down menu, so the user can easily select an equipment type to narrow down the candidate wireless stations to be subjected to interference calculation. When the "equipment type" is selected and the "display" button is pressed, the wireless stations displayed in the list are narrowed down. This allows the user to easily select the wireless stations to be subjected to interference evaluation from the narrowed down wireless stations.

[0296] On the station selection screen ss shown in Fig. 20, the "System Name" list displays "System_55," "System_56," "System_57," "System_58," and "System_59." Here, for example, if only the check box for "System_57" is selected as shown in Fig. 20, a list of wireless stations that use the wireless system corresponding to "System_57" is displayed in the lower section of the station selection screen ss.

[0297] 20, a list of station information for four wireless stations is displayed. For example, the station information displayed at the top of the list has a "Station Name" of "Station 1," a "Station Type" of "Ground Station," a latitude of "36.47.XX," a longitude of "135.21.XX," a "System Name" of "System_57," and a center frequency of "5.XXX (GHz)."

[0298] By selecting station information of a desired wireless station from the station information of multiple wireless stations displayed on the station selection screen ss shown in Fig. 20, the station information of the selected wireless station is set as an execution condition for interference calculation on the execution condition specification screen h1 shown in Fig. 18. For example, on the station selection screen ss shown in Fig. 20, the station information displayed in the second row of the list is selected by a check box. The user selects the station information of the desired wireless station from the list by checking the check box, and presses the "OK" button located at the bottom of the station selection screen ss. This allows the user to easily set the desired wireless station as an interfering station or an interfered station.

[0299] The station selection screen ss shown in Fig. 20 is an example screen for narrowing down the wireless stations to be subjected to interference evaluation by frequency band. However, it is also possible to narrow down the wireless stations by "center frequency" instead of "frequency band." For example, the user may specify "5.000" to "5.999" or "GHz" in the "center frequency" display area displayed on the station selection screen s shown in Fig. 20 and press the "Display" button. This narrows down the candidates for wireless stations to be subjected to interference evaluation by center frequency.

[0300] Generally, different wireless systems using the same frequency band or different wireless systems with similar center frequencies may be affected by interference, so the frequency band and center frequency are important parameters for interference evaluation. When narrowing down the wireless stations to be subject to interference evaluation by center frequency, it is necessary to set a certain range for the center frequency value as a narrowing-down condition, taking into consideration various parameters (e.g., transmission bandwidth, etc.) entered in the station DB editing screen se shown in Fig. 16.

[0301] Below, we will show three examples of specifying the execution conditions for interference calculation (first interference calculation) in map-based interference evaluation. The three examples are "point-to-point calculation," "area calculation," and "interference calculation between a satellite and a ground station."

[0302] In the "calculation of interference between satellites and ground stations," the value of the average road width calculated by the map data processing device in each embodiment of the present invention is not used, and therefore a description thereof will be omitted here.

[0303] First, the "point-to-point calculation" will be described. Fig. 21 is a schematic diagram showing an example of an execution condition specification screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. The execution condition specification screen hp shown in Fig. 21 is an example of a screen for setting the execution conditions for interference calculation by point-to-point calculation.

[0304] 21 is generated by the calculation condition setting unit 16 and displayed by the display unit 302. The calculation condition setting unit 16 also controls the display of the execution condition setting screen hp by the display unit 302 based on information input by the operation input unit 301.

[0305] As shown in the figure, the top row of the execution condition specification screen hp displays an item for specifying the "calculation method." In Figure 21, in the item for specifying the "calculation method," the "point calculation" radio button is checked, thereby selecting calculation between points.

[0306] Here, calculation between points means that when the positions of the interfering station and the interfered station are known, interference calculation is performed based on the positions of the interfering station and the interfered station, and it is determined whether or not the interfered station will be affected by interference.

[0307] As shown in Figure 21, the "Interfered / Interfered Information" display area on the execution condition specification screen HP displays a list of station information for the interfering station and the interfered station selected as targets for interference calculation. As shown in the figure, the station information displayed in this list includes "Interfered / Interfered" which distinguishes between an interfering station and an interfered station, "Station Name", "Latitude 1" and "Longitude 1" which indicate the location where the wireless station is installed, "System Name" which indicates the name of the wireless system used by the wireless station, and "Antenna Name" which indicates the name of the antenna used by the wireless station.

[0308] In addition, the list of station information of interfering stations and station information of interfered stations displayed on the execution condition specification screen hp shown in Fig. 21 includes station information of two interfering stations and station information of two interfered stations, respectively. In other words, four wireless stations are subject to interference evaluation.

[0309] For example, as shown in Fig. 21, the top row of the list displays station information in which "give / receive" is "interference," "station name" is "station 2," "latitude 1" is "35.65X," "longitude 1" is "139.84X," "system name" is "system_52," and "antenna name" is "B." Also, for example, as shown in Fig. 21, the second row of the list is in a selected state, and this second row displays station information in which "give / receive" is "interference," "station name" is "station 3," "latitude 1" is "35.58X," "longitude 1" is "139.74X," "system name" is "system_52," and "antenna name" is "B."

[0310] 21, the bottom of the execution condition specification screen hp displays check boxes for selecting whether to consider three execution conditions for the interference calculation: "attenuation due to terrain," "attenuation due to buildings," and "additional loss." If consideration of these items is selected, attenuation is calculated based on map information including the necessary terrain information and building height information, and the amount of additional loss is set based on the user's judgment and reflected in the interference calculation.

[0311] The necessary topographical information includes, for example, the average road width calculated by the map data processing device in each of the above-described embodiments.

[0312] As a formula for calculating radio wave attenuation in interference calculations (also called a radio wave propagation formula or a propagation loss calculation formula), for example, the square law, a formula for calculating free space loss + ridge loss that takes into account ridges when the line of sight is geographically obstructed, or the formulas described in Japanese Patent Application Laid-Open No. 2013-26884 (formulas (1) to (8) in the patent document) can be used. Furthermore, it is also possible to select the extended Hata formula, the formulas specified in ITU-R Recommendation P.1411, etc.

[0313] For example, one of the variables in the formula for calculating radio wave attenuation in such interference calculations is the value of the average road width.

[0314] Next, the "planar calculation" will be described. Fig. 22 is a schematic diagram showing an example of an execution condition specification screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. The execution condition specification screen hs shown in Fig. 22 is an example of a screen for setting the execution conditions for interference calculation by planar calculation.

[0315] 22 is generated by the calculation condition setting unit 16 and displayed by the display unit 302. The calculation condition setting unit 16 controls the display of the execution condition setting screen hs by the display unit 302 based on information input by the operation input unit 301.

[0316] As shown in the figure, the top row of the execution condition specification screen hs displays an item for specifying the "calculation method." In Figure 22, in the item for specifying the "calculation method," the "area calculation" radio button is checked, thereby selecting area calculation.

[0317] Here, area-wide calculation means that the location of one wireless station (e.g., the interfered station) is fixed, and the area (range) in which the other wireless station (e.g., the interfering station) will be affected by interference is indicated. Specifically, the specified range around the former wireless station (e.g., the interfered station) is divided into a grid (mesh), and the latter wireless station (e.g., the interfering station) is assumed to exist in each grid (mesh), and interference calculation is performed area-wide. This determines the range in which the former wireless station (e.g., the interfered station) will be affected by interference.

[0318] As shown in Figure 22, the display area for "Interfering / Interfered Information" on the execution condition specification screen hs displays a list of station information for interfering stations and interfered stations selected as targets for interference calculation, similar to the execution condition specification screen hp shown in Figure 21.

[0319] As shown in the figure, the station information displayed in this list includes the items "Interfering / Interfered" which distinguish whether the station is an interfering station or an interfered station, "Station Name", "Latitude 1" and "Longitude 1" which indicate the location where the wireless station is installed, "System Name" which indicates the name of the wireless system used by the wireless station, and "Antenna Name" which indicates the name of the antenna used by the wireless station.

[0320] Also, as shown in Figure 22, the lower section of the execution condition specification screen hs displays an item for specifying whether or not to consider attenuation and loss (i.e., a check box for selecting whether or not to consider the three execution conditions of interference calculation, namely, "attenuation due to terrain," "attenuation due to buildings," and "additional loss") that is displayed on the execution condition specification screen hp shown in Figure 21, as well as an "area specification" item (range specification using two latitudes and longitudes) for specifying the area in which interference calculation is to be performed, and an "antenna direction of interfering station" item.

[0321] In the "Antenna Direction of Interfering Station" section, if "Worst" (i.e., the worst condition) is specified, the interference calculation is performed for the case where the antenna direction of the interfering station is always facing the interfered station. When the antenna of the interfering station is facing the interfered station, the amount of interference is greatest.

[0322] In addition, in the "Antenna Direction of Interfering Station" item, it is possible to calculate the amount of interference by specifying the antenna direction of the interfering station by north, south, east, or west, or by specifying it to always be at a constant angle relative to the direction of the interfered station. As shown in Figure 22, the "Antenna Direction of Interfering Station" is selected using the radio buttons.

[0323] As a formula for calculating radio wave attenuation in interference calculation (also called radio wave propagation formula or propagation loss calculation formula), for example, the square law, the formula for calculating free space loss + ridge loss, or the formulas described in Japanese Patent Application Laid-Open No. 2013-26884 (formulas (1) to (8) in the patent document) can be used. Furthermore, it is also possible to select the extended Hata formula, the formulas specified in ITU-R Recommendation P.1411, etc.

[0324] For example, one of the variables in the formula for calculating radio wave attenuation in such interference calculations is the value of the average road width.

[0325] In this way, the execution condition specification screen is displayed in a basically common display format for the calculation conditions for the three different calculations (i.e., "point-to-point calculation," "area calculation," and "satellite-to-ground station interference calculation"). Furthermore, depending on the calculation conditions, it is determined whether or not each item needs to be set. Then, according to this determination result, it is set whether or not input to each item is possible. This allows the user to easily recognize the items that need to be set, making it easier to execute interference calculations.

[0326] The following describes the display of calculation results of interference calculations in map-based interference assessment. Fig. 23 is a schematic diagram showing an example of a calculation result display screen displayed by the interference assessment device 1 according to one embodiment of the present invention. Fig. 23 shows a result display screen rp that shows the calculation results obtained by point-to-point calculations, and a result display screen rs that shows the calculation results obtained by planar calculations.

[0327] 23 are generated by the calculation result display designation unit 17 and displayed by the display unit 302. The calculation result display designation unit 17 controls the display of the result display screen rp and the result display screen rs by the display unit 302 based on information input by the operation input unit 301. These two result display screens are switched by selecting the "Individual Evaluation Result" tab and the "Map Display" tab, respectively, as shown in FIG.

[0328] The "Individual Evaluation Results" display area on the calculation result display screen rp shows the calculation results for the four radio stations selected as the targets for interference evaluation on the execution condition specification screen hp shown in Figure 21 when interference calculation is performed using the interference calculation execution conditions set on the execution condition specification screen hp shown in Figure 21.

[0329] In addition, the "Map Results" display area on the calculation result display screen rs shows the calculation results for the radio stations selected as the targets for interference evaluation on the execution condition specification screen hp shown in Figure 22 when interference calculation is performed according to the execution conditions for interference calculation set on the execution condition specification screen hs shown in Figure 22.

[0330] In both the calculation result display screen rp and the calculation result display screen rs, the interfering station and the interfered station that are the targets of the interference calculation, and the calculation conditions are displayed in the upper part of the screen.

[0331] The calculation result display screen rp also displays a display area for setting the execution conditions for the evaluation calculation, which specifies whether or not to consider attenuation and additional loss due to directivity. A profile diagram is displayed depending on the selection of the execution conditions for this interference calculation. The profile display will be explained in detail later.

[0332] In addition, the bottom of the calculation result display screen rp displays a list showing the combinations of interfering and interfered stations to be evaluated and the calculation results. Here, when "Station 2" and "Station 3" are the interfering stations and "Station 1" and "Station 4" are the interfered stations, the numerical values ​​of the interference calculation results for each combination of the interfering and interfered stations are displayed. Also displayed are information (numerical values) indicating the determination result of whether the numerical values ​​of the interference results (numerical values ​​in parentheses) are acceptable values, and information (using "○" or "×" marks) indicating whether the interference calculation results are acceptable.

[0333] The calculation result display screen rs displays a display area for setting the execution conditions for the evaluation calculation, which specifies whether or not to consider attenuation due to directivity and additional loss. In addition, the bottom section of the calculation result display screen rs displays radio buttons for selecting whether to calculate taking into account attenuation due to terrain, attenuation due to buildings, or to calculate the worst value without considering either. A map is displayed depending on the selection of the execution conditions for this interference calculation. Map display will be explained in detail later.

[0334] An example of the display results of interference calculation between points, for which display conditions have been set, is shown below on the calculation result display screen rp shown in Fig. 23. Fig. 24 is a schematic diagram showing an example of an interference evaluation result screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. Fig. 24 shows an interference evaluation result screen mp which displays the calculation results of interference calculation between points on a map, and an interference evaluation result screen pf which displays the calculation results of interference calculation between points on a profile diagram.

[0335] 24 are generated by the calculation result diagram display unit 19 and displayed by the display unit 302. The calculation result diagram display unit 19 controls the display of the interference evaluation result screen mp and the interference evaluation result screen pf by the display unit 302 based on information input by the operation input unit 301.

[0336] The interference evaluation result screen mp shows the relative positions and distances of two interfering stations and two interfered stations on a map. Note that wireless stations displayed with solid triangles indicate wireless stations for which the checkbox displayed in the "File" column on the left side of the map is selected. Wireless stations displayed with dashed triangles indicate wireless stations for which the checkbox displayed in the "File" column on the left side of the map is not selected.

[0337] Furthermore, on the map shown on the interference evaluation result screen mp, the distances from the interfering station whose check box is selected to the two interfered stations are shown to be "2.4 km" and "1.7 km," respectively, as shown in Fig. 24. Also, the map shows that the antenna directions of the three wireless stations (one interfering station and two interfered stations whose check boxes are selected) are 320° (north-northwest), 120° (almost southeast), and 85° (almost south), respectively, clockwise (with north as the reference direction, 0°).

[0338] In addition, in the file column displayed on the left side of the map, items indicating the two interfering stations and two interfered stations shown on the map of the interference evaluation result screen mp, the straight-line distances between the two pairs of interfered stations and interfered stations, etc. are displayed in a tree format as a parts list. In this tree display, the user can switch whether or not to display each part by selecting a check box.

[0339] The profile diagram displayed on the interference evaluation result screen pf shows the situation, such as changes in the terrain and the presence of buildings, on the line connecting a specific interfering station and a specific interfered station. The interference evaluation result screen pf shown in Figure 24 shows that the antenna heights of both the interfering station and the interfered station are approximately 10 m. It also shows that the distance between the interfering station and the interfered station is approximately 2.4 km. It also shows that the terrain on the line connecting the interfering station and the interfered station is undulating, although it is less than 80 m, so they cannot see each other. It also shows that the interference wave extends mainly beyond two edges.

[0340] In this way, by displaying the locations of the interfering and interfered-with stations on the map display or profile display, the user can easily understand the relative positions of the wireless stations.

[0341] Fig. 25 is a schematic diagram showing an example of a calculation result screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. Fig. 25 shows a calculation result display screen rs2 that shows the calculation results of interference calculation by planar calculation.

[0342] 25 is generated by the calculation result display designation unit 17 and displayed by the display unit 302. The calculation result display designation unit 17 controls the display of the result display screen rs2 by the display unit 302 based on information input by the operation input unit 301.

[0343] The calculation result display screen rs2 shown in Fig. 25 shows the state after calculation conditions have been set separately and calculation has been performed. The calculation result display screen rs2 shows the display condition selection items when displaying the calculation results of the interference calculation. As shown in Fig. 25, the selection items for the conditions for displaying the calculation results of the interference calculation include an item for selecting whether or not to consider attenuation due to directivity, and an item for selecting whether or not to consider additional loss.

[0344] Furthermore, as shown in FIG. 25, the conditions for displaying the results of interference calculations include the option to select whether or not to consider attenuation due to terrain, whether or not to consider attenuation due to buildings, or whether to use the worst case value that does not consider attenuation due to terrain or attenuation due to buildings.

[0345] The calculation result display screen rs2 shown in Figure 25 represents a state in which the conditions are set such that the amount of attenuation due to directivity and additional loss are taken into account in the interference calculation, and the amount of interference is calculated on a surface basis using the worst-case value without taking into account attenuation due to terrain or buildings.

[0346] Fig. 26 is a schematic diagram showing an example of an interference evaluation result screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. Fig. 26 shows an interference evaluation result screen mp2 that displays the calculation results of interference calculation based on planar calculation on a map.

[0347] 26 is generated by the calculation result diagram display unit 19 and displayed by the display unit 302. The calculation result diagram display unit 19 controls the display of the interference evaluation result screen mp2 by the display unit 302 based on information input by the operation input unit 301.

[0348] The interference evaluation result screen mp2 shows on a map the range of unacceptable and acceptable interference effects from the interfering station on the interfered station. That is, the range of unacceptable interference effects is shown on the map as an "interference area," and the range of acceptable interference effects is shown on the map as an interference-acceptable area.

[0349] The map displayed on the interference evaluation result screen mp2 shows the location of the interfered station, with the interfered station's directional antenna pointed in the southeast direction. This shows that the area affected by interference (interference area) extends southeast from the interfered station (to the lower right in Figure 27). An example is shown of an interfering station located on the boundary between the interference area and the interference-tolerance area.

[0350] In addition, in the file column displayed to the left of the map, items showing the interfering station, interfered station, interference area, interference-tolerance area, etc. shown on the map of the interference evaluation result screen mp2 are displayed in a tree format as a parts list. The user can select whether or not to display each part in this tree format by selecting a check box.

[0351] It has been described above that the results of interference calculations can be displayed on a profile diagram or a map, such as the interference evaluation result screen pf, interference evaluation result screen mp, or interference evaluation result screen mp2. The following describes how the interference evaluation device 1 can present the influence of interference caused by all of a plurality of interfering stations on one interfered station (total influence of interference) from each calculation result of interference calculation between individual interfering stations and interfered stations, without recalculating the influence. This presentation can be realized, for example, by simply changing some of the settings related to the execution conditions of the interference calculations set on the execution condition specification screen hp shown in FIG. 21 or the settings related to the display of the calculation results set on the calculation result display screen rp or the calculation result display screen rs shown in FIG. 23.

[0352] As described above, the calculation conditions for the interference calculation are set on the execution condition specification screen hp shown in Fig. 21. The conditions for the interference calculation set on the execution condition specification screen hp will be described in more detail below.

[0353] As described above, a list of station information of wireless stations to be subjected to interference evaluation is displayed in the upper section of the execution condition specification screen hp shown in Fig. 21. Note that four wireless stations are selected on the execution condition specification screen hp shown in Fig. 21, and the station information of each of these four wireless stations is displayed.

[0354] As shown in the figure, in the station information displayed at the top of the list of station information for wireless stations that are the subject of interference assessment, the value of the "interference / received" field indicating the type of interference is "interfering," indicating the interfering station that causes interference, the "station name" is "station 2," the "latitude 1" and "longitude 1" indicating the latitude and longitude of the location where the wireless station is installed are "35.65X" and "139.84X," respectively, the "system name" is "system_52," and the "antenna name" is "B." Also, as shown in the figure, the station information displayed in the second row of the list of station information for wireless stations that are the subject of interference assessment is highlighted. In the station information displayed in the second row of the list of station information for the radio station being evaluated for interference, the type of interference ("giving / receiving") is "interference," the "station name" is "Station 3," the "latitude 1" and "longitude 1" are "35.58X" and "139.74X," respectively, the "system name" is "System_52," and the "antenna name" is "B."

[0355] Also, as shown in the figure, in the station information displayed in the third row of the list of station information for wireless stations that are the subject of interference assessment, the value of the "give / receive" item indicating the type of interference is "interfered with," indicating that the interfered station is interfered with, the "station name" is "station 4," the "latitude 1" and "longitude 1" are "35.46X" and "139.62X," respectively, the "system name" is "system_52," and the "antenna name" is "A." Also, as shown in the figure, in the station information displayed in the fourth row (bottom row) of the list of station information for wireless stations that are the subject of interference assessment, the value of the "give / receive" item indicating the type of interference is "interfered with," the "station name" is "station 1," the "latitude 1" and "longitude 1" are "35.39X" and "139.58X," respectively, the "system name" is "system_51," and the "antenna name" is "A."

[0356] In the lower section of the execution condition specification screen HP shown in Figure 21, calculation conditions for interference calculation other than station information are selected and specified. The execution condition specification screen HP shown in Figure 21 specifies that interference calculation taking into account attenuation due to terrain will be performed using the "square law + ridge loss" method. In other words, the amount of interference will be calculated taking into account not only power attenuation over distance in free space but also attenuation due to terrain such as mountains and hills. Also, the "Consider attenuation due to buildings" option is not selected. Also, it is set to take into account additional loss of a specified value (unit: dB).

[0357] In the interference calculation that takes into account attenuation due to the terrain, for example, the average road width calculated by the map data processing device in each of the above-mentioned embodiments is also taken into account.

[0358] As described above, the execution condition specification screen hp shown in Fig. 21 is set to target interference evaluation for two interfering stations and two interfered stations. The user can change the targets of interference evaluation (for example, to target three interfering stations and one interfered station) by simply making a partial change to this setting.

[0359] The following describes a case where interference calculation is performed under settings in which only the type of target station is changed among the calculation conditions for interference calculation set on the execution condition specification screen hp shown in FIG.

[0360] Fig. 27 is a schematic diagram showing an example of a calculation result display screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. In Fig. 27, a calculation result display screen rp2 and a calculation result display screen rp3 are displayed.

[0361] 27 are generated by the calculation result display designation unit 17 and displayed by the display unit 302. The calculation result display designation unit 17 controls the display of the calculation result display screen rp2 and the calculation result display screen rp3 by the display unit 302 based on information input by the operation input unit 301.

[0362] The calculation results of the interference calculation are displayed in the lower section of the calculation result display screen rp2. As shown in FIG. 27, there are three tabs ("Individual Evaluation Results," "Overall Evaluation Results," and "Map Display") in the lower section of the calculation result display screen rp2. When the "Individual Evaluation Results" tab is selected on the calculation result display screen rp2 shown in FIG. 27, a list showing the combinations of the interfering station and the interfered station that are the subject of the interference calculation and the calculation results is displayed. As shown in FIG. 27, the calculation result display screen rp2 displays three calculation results in a list.

[0363] The top row of the list shown on the calculation result display screen rp2 shows that for a combination of wireless stations where the interfering station is "Station 2" and the interfered station is "Station 4," the calculation result for the worst case scenario where the antenna of the interfering station is pointing in the direction of the interfered station is "○" (i.e., the result shows that the impact of interference is within an acceptable range), and the margin for the required I / N (threshold) for allowable interference is "2.9 dB." Furthermore, the calculation result for interference calculation taking into account the terrain is "○," and the calculation result shows that the margin for the required I / N for allowable interference is "13.2 dB."

[0364] The second row of the list shown on the calculation result display screen rp2 shows that for a combination of radio stations where the interfering station is "Station 3" and the interfered station is "Station 4," the calculation result for the worst case scenario where the antenna of the interfering station is pointing in the direction of the interfered station is "○," and the margin for the required I / N for allowable interference is "10.7 dB." Furthermore, the calculation result for interference calculation taking into account the terrain is "○," and the calculation result for the margin for the required I / N for allowable interference is "38.3 dB."

[0365] The third row of the list shown on the calculation result display screen rp2 shows that for a combination of radio stations where the interfering station is "Station 1" and the interfered station is "Station 4," the calculation result for the worst case scenario where the antenna of the interfering station is pointing in the direction of the interfered station is "○," and the margin for the required I / N for allowable interference is "5.4 dB." Furthermore, the calculation result for interference calculation taking into account the terrain is "○," and the calculation result for the margin for the required I / N for allowable interference is "16.7 dB."

[0366] In this way, when the "Individual Evaluation Results" tab is selected on the calculation result display screen rp2, the calculation results for each interference calculation for a combination of one interfering station and multiple (three) interfered stations are displayed.

[0367] Here, when the "Overall Evaluation Result" tab is selected on the calculation result display screen rp2, the screen that appears is the calculation result display screen rp3 shown in Fig. 27. The calculation result display screen rp3 displays the overall evaluation result that is a compilation of all the calculation results of the evaluation calculations for the three combinations of interfering station and interfered station mentioned above (i.e., the combinations of "Station 2" and "Station 4", "Station 3" and "Station 4", and "Station 1" and "Station 4").

[0368] As shown in Fig. 27, the calculation result display screen rp3 shows the overall evaluation result when the interfering stations are "Station 2," "Station 3," and "Station 1," and the interfered station is "Station 4." This overall evaluation result shows that the calculation result for the worst case is "x," and the margin for the required I / N for allowable interference is a negative value of "-4.1 dB." This overall evaluation result also shows that the calculation result for the interference calculation when taking the terrain into consideration is "o," and the margin for the required I / N for allowable interference is "8.2 dB."

[0369] In this way, when performing interference calculations for a combination of multiple interfering stations and interfered stations, even if the individual calculation results are all ``○'' (i.e., the result is that the interference is within an acceptable range), when the effects of interference from all of the multiple interfering stations on one interfered station are combined, the result of the interference calculation may be ``×'' (i.e., the result is that the effects of interference are within an unacceptable range).

[0370] If interference calculations that take into account the effects of multiple interfering stations, which can result in such calculation results, are performed using conventional general-purpose spreadsheet software (as described at the beginning with reference to Figures 37 and 38), the work becomes complicated and places a heavy burden on the user. In this example, there are three interfering stations and one interfered station, for a total of three combinations of interfering / interfered stations. However, if there are 10 interfering and 10 interfered stations, the total number of combinations becomes 100, which makes conventional interference analysis methods cumbersome and requires an even greater amount of work.

[0371] On the other hand, with the above-described interference evaluation device 1, the user can refer to the calculation of the interference evaluation without performing any complicated work by simply setting the calculation conditions for the interference calculation on the execution condition specification screen hp shown in Fig. 21 and selecting the "Overall evaluation result" tab as shown on the calculation result display screen rp3 shown in Fig. 27. Furthermore, on the calculation result display screen rp3, the user can easily see whether the margin for the allowable interference required I / N is a positive value or not, and the numerical value of the margin.

[0372] In this way, on the calculation result display screen rp3 shown in Fig. 27, the evaluation results regarding the influence of interference from an individual interfering station to an interfered station and the evaluation results regarding the influence of interference from multiple interfering stations to an interfered station can be displayed simply by switching between the "individual evaluation result" tag and the "overall evaluation result" tag. This makes it easy to compare multiple interfering stations in order to avoid the influence of interference, or to consider whether the influence of interference can be avoided by excluding a specific interfering station.

[0373] For example, the interference calculation for obtaining the "individual evaluation result" displayed on the calculation result display screen rp2 and the interference calculation for obtaining the "overall evaluation result" displayed on the calculation result display screen rp3 are started by pressing the "Execute calculation" button located on the execution condition specification screen. Therefore, when the calculation result display screen rp2 or the calculation result display screen rp3 shown in Figure 27 is displayed, the "individual evaluation result" and the "overall evaluation result" have already been obtained.

[0374] Screen transitions relating to map-based interference assessment will be described below. Fig. 28 is a screen transition diagram showing the transition of screens displayed by the interference assessment device 1 according to one embodiment of the present invention. The screen transition diagram shown in Fig. 28 shows the state of screen transitions in map-based interference assessment (i.e., interference assessment when at least one of the position of the interfering station and the position of the interfered station is known).

[0375] In the screen transition diagram shown in Figure 28, the main screens that are displayed are indicated by solid line boxes. As shown in the figure, the main screens are the "Menu" screen, the "Calculation Condition Setting (Map)" screen, the "History Selection and Use" screen, and the "Calculation Result (Map) Display and Setting" screen.

[0376] The "Menu" screen here corresponds to the main menu screen m shown in Fig. 13. The "Calculation Condition Setting (Map)" screen here corresponds to the execution condition specification screen h1 shown in Fig. 18, the execution condition specification screen hp shown in Fig. 21, and the execution condition specification screen hs shown in Fig. 22. The "History Selection and Use" screen here corresponds to the history selection screen h2 shown in Fig. 19. The "Calculation Result (Map) Display and Setting" screen here corresponds to the calculation result display screen rp and calculation result display screen rs shown in Fig. 23, and the calculation result display screen rp2 and calculation result display screen rp3 shown in Fig. 27.

[0377] In addition, in the screen transition diagram shown in Figure 28, screens other than the above-mentioned main screens (hereinafter referred to as "sub-screens") are displayed, which are enclosed by dashed lines. As shown in the figure, the sub-screens are the "Edit Station Information" screen, the "Select Interfering Station / Interfered Station" screen, the "Execute Calculation" screen, the "Display Antenna Pattern" screen, the "Display Profile" screen, the "Display Result Map" screen, and the "Display Heat Map" screen.

[0378] The "Station Information Edit" screen referred to here corresponds to the Station DB Edit screen se shown in FIG. 16. The "Select Interfering Station / Interfered Station" screen referred to here corresponds to the Station Selection screen ss shown in FIG. 20. The "Profile Display" screen referred to here corresponds to the Interference Evaluation Result screen pf shown in FIG. 24. The "Result Map Display" screen referred to here corresponds to the Interference Evaluation Result screen mp shown in FIG. 24. The "Heat Map Display" screen referred to here corresponds to the Interference Evaluation Result screen mp2 shown in FIG. 26. The "Calculation Execution" screen is a screen that shows the state in which an interference calculation is being executed, and the "Antenna Pattern Display" screen is a screen that displays the antenna pattern, but detailed explanations thereof will be omitted.

[0379] In addition, in the screen transition diagram shown in Figure 28, the description attached to the arrow indicating the transition between screen states shows an example of a method of instructing the transition on the screen from which the transition originates, and indicates, for example, the name of the button to be pressed.

[0380] As shown in the screen transition diagram in Figure 28, the "Edit Station Information" screen and the "Select Interfering Station / Interfered Station" screen can be accessed from the "Calculation Setting Conditions (Map)" screen. This allows the user to edit the station information of wireless stations related to interference evaluation from the "Calculation Setting Conditions (Map)" screen, or to select an interfering station or an interfered station to be used in interference calculation and read out the station information.

[0381] In addition, the transition from the "Calculation Condition Setting (Map)" screen to the "Calculation Execution" screen is made by pressing the "Calculation Execution" button located on the execution condition specification screen h1 shown in FIG. 18, the execution condition specification screen hp shown in FIG. 21, or the execution condition specification screen hs shown in FIG. 22, after all execution conditions for the interference calculation have been set.

[0382] In addition, the "Calculation Results (Map) Display and Settings" screen can be used to transition to the "Profile Display" screen, the "Results Map Display" screen, and the "Heat Map Display" screen. This allows users to select the desired display method on the "Calculation Results (Map) Display and Settings" screen and view the results of interference calculations.

[0383] The "Antenna Pattern Display" screen can be accessed from either the "Calculation Condition Setting (Map)" screen or the "Calculation Result (Map) Display / Setting" screen. This allows the user to check the antenna pattern both before and after performing an interference calculation.

[0384] The following describes screen transitions in setting the execution conditions for interference calculation when history selection is performed in interference evaluation. Fig. 29 is a screen transition diagram showing transitions of screens displayed by the interference evaluation device 1 according to one embodiment of the present invention.

[0385] In the above, as screens equivalent to the "Calculation Condition Setting (Map)" screen, the execution condition specification screen hp for specifying the execution conditions for calculation between points shown in Fig. 21 and the execution condition specification screen hs for specifying the execution conditions for area calculation shown in Fig. 22 have been described. The control unit 10 of the interference evaluation device 1 automatically determines which of these execution condition specification screens to transition to.

[0386] Specifically, of the radio buttons located at the top of the execution condition specification screen hp shown in Figure 21 and the execution condition specification screen hs shown in Figure 22, if "Point calculation" is selected, the screen will automatically switch to the execution condition specification screen hp, and if "Area calculation" is selected, the screen will automatically switch to the execution condition specification screen hs.

[0387] In addition, on the history selection screen h2 shown in Figure 19, if the history folder for "point calculation" is selected, the screen will automatically transition to the execution condition specification screen hp, and if the history folder for "area calculation" is selected, the screen will automatically transition to the execution condition specification screen hs.

[0388] [Model-based interference assessment] Model-based interference evaluation will be described below. Fig. 30 is a schematic diagram showing an example of an interference evaluation result screen displayed by the interference evaluation device 1 according to one embodiment of the present invention. Fig. 30 shows an interference evaluation result screen mp3 which displays the calculation results of interference calculation (second interference calculation) by model-based interference evaluation on a map.

[0389] 30 is generated by the calculation result diagram display unit 19 and displayed by the display unit 302. The calculation result diagram display unit 19 controls the display of the interference evaluation result screen mp3 by the display unit 302 based on information input by the operation input unit 301.

[0390] The interference evaluation result screen mp3 shown in Figure 30 shows the interfered station, separation distance, and ridge distance on a map. Also shown are the separation distance calculated using the worst-case scenario and the separation distance calculated under calculation conditions with a ridge. The separation distance calculated under calculation conditions with a ridge is a separation distance that takes into account points that block the line of sight from the interfered station based on the topography on the map. The separation distance calculated using the worst-case scenario is a separation distance calculated under calculation conditions that do not take into account the ridge caused by such topography.

[0391] The ridge distance indicates the position of the ridge when calculating the separation distance under calculation conditions with a ridge. On the map of the interference evaluation result screen mp3 shown in Figure 30, the ridge distance represents the distance that is half the length of the worst-case value (the distance from the interfered station). Note that the separation distance here refers to the distance required for the interfered station to not be affected by interference.

[0392] In this way, the interference evaluation device 1 not only displays the calculation results of the interference calculation using the map-based interference evaluation described above on a map, but can also display the calculation results of the interference calculation using the model-based interference evaluation on a map in addition to displaying them in text.

[0393] Screen transitions relating to model-based interference evaluation will be described below. Fig. 31 is a screen transition diagram showing the transition of screens displayed by the interference evaluation device 1 according to one embodiment of the present invention. The screen transition diagram shown in Fig. 31 shows the state of screen transitions in model-based interference evaluation (i.e., interference evaluation when both the position of the interfering station and the position of the interfered station are unclear).

[0394] In the screen transition diagram shown in Figure 31, the state in which the main screens are displayed is indicated by a solid line box. As shown in the figure, the main screens are the "Menu" screen, the "Calculation Condition Setting (Model)" screen, the "History Selection and Use" screen, and the "Calculation Result (Model) Display and Setting" screen. The "Menu" screen here corresponds to the main menu screen m shown in Figure 13. The "History Selection and Use" screen here corresponds to the history selection screen h2 shown in Figure 19.

[0395] In addition, in the screen transition diagram shown in Fig. 31, the state in which a sub-screen is displayed is indicated by a dashed line box. As shown in the figure, the sub-screens are the "Calculation execution" screen, the "Antenna pattern display" screen, the "Results map display" screen, and the "Station selection" screen. The "Results map display" screen here corresponds to the interference evaluation results screen mp3 shown in Fig. 30.

[0396] In addition, in the screen transition diagram shown in Figure 31, the description attached to the arrow indicating the transition between screen states shows an example of a method of instructing the transition on the screen from which the transition originates, and indicates, for example, the name of the button to be pressed.

[0397] As shown in Figure 31, in model-based interference assessment, as with map-based interference assessment, you can transition from the "Calculation Condition Setting (Model)" screen to the "History Selection and Use" screen. Also, as with map-based interference assessment, all execution conditions for interference calculation are set on the "Calculation Condition Setting (Model)" screen, and by pressing the "Execute Calculation" button, you will transition to the "Calculation Result (Model) Display and Settings" screen via the "Execute Calculation" screen.

[0398] Also, as shown in Figure 31, just like map-based interference assessment, the "Antenna Pattern Display" screen can be accessed from either the "Calculation Condition Setting (Model)" screen or the "Calculation Result (Model) Display / Setting" screen. Here, what differs from map-based interference assessment is that it is possible to transition from the "Calculation Result (Model) Display / Setting" screen to the "Station Selection" screen. As a result, even in interference calculations using model-based interference assessment, the calculation results are projected onto a map as specific locations of the range of interference influence, allowing the user to visually recognize the effects of interference.

[0399] Screen transitions relating to history selection and use will be described below. Fig. 32 is a screen transition diagram showing transitions of screens displayed by the interference evaluation device 1 according to one embodiment of the present invention.

[0400] In the screen transition diagram shown in FIG. 32, the transitions from the "Calculation Condition Setting (Map)" screen and the "Calculation Condition Setting (Model)" screen to the "Calculation Execution" screen and the "Calculation Result Display" screen are omitted. For reference, the transitions from the "Menu" screen to the "Station DB Management" screen and the "Station DB Edit" screen are also shown. The "Station DB Management" screen here corresponds to the station DB management screen sm shown in FIG. 15. The "Station DB Edit" screen here corresponds to the station DB edit screen se shown in FIG. 16.

[0401] As shown in Figure 32, it is possible to transition from the "Menu" screen to both the "Calculation Condition Setting (Map)" screen and the "Calculation Condition Setting (Model)" screen. The "Calculation Condition Setting (Map)" screen is a screen for setting the execution conditions for interference calculations using map-based interference evaluation that uses detailed information on the interfering station and the interfered station. The "Calculation Condition Setting (Model)" screen is a screen for setting the execution conditions for interference calculations using model-based interference evaluation that does not require detailed information on the interfering station and the interfered station.

[0402] In addition, the "Calculation Condition Setting (Simple Station Design)" screen, which is a screen for setting calculation conditions in simple station design that uses information indicating the positions of the interfering and interfered stations, similar to map-based interference evaluation, and the "Calculation Condition Setting (Interference Wave Level Calculation)" screen, which is a screen for calculating interference wave levels, can be accessed by pressing the appropriate button on the "Menu" screen.

[0403] From the "Calculation Condition Setting (Map)" screen, "Calculation Condition Setting (Simple Station Placement Design)" screen, and "Calculation Condition Setting (Interference Level Calculation)" screen, you can transition to the "Selection of Interfered / Interfered Stations" screen. Once the radio stations to be subject to interference evaluation are set here, the screen transitions back to the "Calculation Condition Setting (Map)" screen.

[0404] In addition, by pressing the appropriate button on the "Menu" screen, you can transition to the "Calculation Condition Setting (Model)" screen, which is a screen for setting the execution conditions for interference calculations using model-based interference evaluation that does not require detailed information on the interfering and interfered-with stations.

[0405] Furthermore, it is possible to transition to the "History Selection and Use" screen from either the "Calculation Condition Setting (Map)" screen or the "Calculation Condition Setting (Model)" screen, which can be transitioned to from the "Menu" screen described above. For example, pressing the "History Selection" button located on the execution condition specification screen h1 shown in Fig. 18, the execution condition specification screen hp shown in Fig. 21, or the execution condition specification screen hs shown in Fig. 22 transitions to the history selection screen h2 shown in Fig. 19.

[0406] The history storage unit 202, which is referenced from the "History Selection Use" screen, stores a history folder containing the history of interference assessments that have been performed in the past. From this history folder, it is possible to read out, for example, the execution conditions of similar past interference calculations and use them as the execution conditions for the interference calculation. At this time, it is also possible to select a history information folder corresponding to execution conditions different from the execution conditions that have already been set. For example, even when transitioning from the "Calculation Condition Setting (Map)" screen, which is used to set up map-based interference assessment, to the "History Selection Use" screen, if a history folder for model-based interference calculations is selected, transition will be made to the "Calculation Condition Setting (Model)" screen, which is different from the screen from which transition was made.

[0407] In this way, the interference assessment menu provided by the interference assessment device 1 includes map-based interference assessment, model-based interference assessment, simple station placement design, etc., but station information required for any interference assessment can all be selected and used from the common station DB 201. Various parameters used in interference studies are entered and registered on the station DB editing screen se shown in Fig. 16, but not all of the various registered parameters are always used in all types of interference assessment.

[0408] However, some parameters (common parameters) are used in common in all interference assessments, while other parameters (individual parameters) are used only in specific interference assessments. The interference assessment device 1 manages both common parameters and individual parameters together in the station DB 201, so that necessary station information can be read from the common station DB 201 for each of the different types of interference assessments provided as selection menus. In this way, being able to obtain necessary station information from the common station DB 201 is highly effective in facilitating interference assessment. This is because, in interference assessment, information such as the design specifications and installation status of the wireless stations to be subject to interference assessment is collected, and interference calculations are performed based on the various pieces of collected information.

[0409] [Linkage between interference assessment device and map data processing device] The following describes the cooperation between the interference evaluation device 1 and the map data processing device 100 (or 100a, 100b) in each of the above-mentioned embodiments. Fig. 33 is a schematic diagram showing an overview of the cooperation between the interference evaluation device 1 and the map data processing device in one embodiment of the present invention. Fig. 34 is a flowchart showing the flow of the cooperation process between the interference evaluation device 1 and the map data processing device in one embodiment of the present invention.

[0410] As shown in FIG. 33, first, the interference evaluation device 1 and the map data processing device 100, 100a or 100b (hereinafter collectively referred to as "map data processing device 100") both acquire in advance map information (hereinafter also referred to as "primary information") indicating a map of the range to be subjected to interference evaluation.

[0411] The primary information may be configured such that the interference evaluation device 1 requests the map data processing device 100 to acquire the primary information, and the interference evaluation device 1 acquires the primary information via the map data processing device 100.

[0412] 33 shows a configuration in which the map information DB 203 is placed outside the map data processing device 100, but the present invention is not limited to such a configuration. For example, the map information DB 203 may be configured to be provided in the interference evaluation device 1 as shown in the above-mentioned FIG. 12, or may be configured to be provided in the map data processing device 100.

[0413] 34, the interference evaluation device 1 transmits a message requesting the value of the average road width to the map data processing device 100 (step S301). Note that the information requested by this message only needs to include at least the value of the average road width, and may further include other necessary information (information that the map data processing device 100 can analyze from the map information).

[0414] Next, when the map data processing device 100 receives the message transmitted from the interference evaluation device 1, it executes the processing described in each of the above-described embodiments to analyze the map data and calculate the average road width value (hereinafter also referred to as "secondary information") of the roads within the evaluation target range e. The map data processing device 100 returns the secondary information calculated based on the map to the interference evaluation device 1 (step S302).

[0415] Next, the interference evaluation device 1 acquires the secondary information returned from the map data processing device 100. The interference evaluation device 1 automatically sets the returned values ​​as input conditions for interference calculation, and executes interference evaluation (step S303). This completes the cooperative processing between the interference evaluation device 1 and the map data processing device 100 shown in the flowchart of Fig. 34.

[0416] Generally, map information itself (i.e., primary information) is often insufficient as the necessary information to perform highly accurate interference assessment. As in this embodiment, the interference assessment device 1 can perform more accurate interference assessment by working in conjunction with a map data processing device 100 that can analyze the primary information of a map and calculate secondary information (such as the value of the average road width). Furthermore, even if the amount of required secondary information changes or increases, this can be handled by replacing or updating the map data processing device 100 according to this embodiment, making it possible to build a more flexible interference assessment system.

[0417] The following describes screen transitions in the interference evaluation device 1 during interference evaluation when the interference evaluation device 1 and the map data processing device 100 cooperate as described above. Fig. 35 is a screen transition diagram showing the transitions of screens displayed by the interference evaluation device 1 according to one embodiment of the present invention. The screen transitions shown in Fig. 35 are obtained by extracting only the screen transitions during interference evaluation when the interference evaluation device 1 and the map data processing device 100 cooperate as described above from the screen transitions shown in Fig. 28 above, with necessary transition conditions added.

[0418] In the screen transition diagram shown in Figure 35, the states of the main operation screens in the interference assessment software, namely the menu screen, calculation condition setting screen, calculation in progress screen, and calculation result display / setting screen, are each indicated by an oval. First, when the interference assessment software is started in the interference assessment device 1, the menu screen is displayed. This makes it possible to select each function implemented in the interference assessment software.

[0419] Note that Figure 35 only shows an excerpt of screen transitions related to functions related to simple station placement study that takes interference evaluation into account. When simple station placement study is selected on the menu screen, the screen transitions to a calculation condition setting screen. This calculation condition setting screen also includes an operation menu for acquiring the value of the average road width from the map data processing device 100 described above. The calculation condition setting screen is used to select the propagation loss formula used in the calculation of interference evaluation by the user and to automatically substitute the value of the average road width into the variable of the propagation loss formula.

[0420] Once all calculation conditions for interference assessment have been set on the calculation condition setting screen and the calculation execution button is pressed, the screen will transition to a calculation in progress screen, which indicates that the interference assessment calculation is currently in progress. Once the calculation is complete, the screen will transition to the calculation result display / setting screen. This allows the user to check the results of the interference assessment and confirm whether or not interference has occurred.

[0421] When an operation to close the calculation condition setting screen is performed, the screen transitions again to return to the calculation condition setting screen, and when an operation to close the calculation condition setting screen is performed again, the screen transitions again to return to the menu screen.

[0422] Fig. 36 is a schematic diagram showing an example of an execution condition specification screen displayed by the interference assessment device 1 according to one embodiment of the present invention. The execution condition specification screen hr shown in Fig. 36 is a screen corresponding to the execution condition specification screen hs shown in Fig. 22 described above, and a user interface for acquiring and automatically setting the value of the average road width used in interference assessment has been added to the execution condition specification screen hr shown in Fig. 36. In addition, in terms of screen transitions, the execution condition specification screen hr shown in Fig. 36 is a screen corresponding to the calculation condition setting screen shown in Fig. 35.

[0423] On the execution condition specification screen hr, it is possible to select the calculation conditions (for example, a propagation loss formula, etc.) to be used in the interference evaluation and to instruct the start of the calculation of the interference evaluation. Also, on the execution condition specification screen hr, it is possible to request information required for the interference evaluation (for example, the value of the average road width) from the map data processing device 100 and to obtain the required information from the map data processing device 100. Note that, before the calculation starts, it is also possible to transition from the execution condition specification screen hr to a station information editing screen for editing station information related to the radio station to be evaluated.

[0424] For example, on the execution condition specification screen hr illustrated in Fig. 36, four main types of execution condition specifications are performed. As shown in Fig. 36, the four execution condition specifications are, for example, specification of transmitting station information, specification of simple station placement study specifications, specification of area, and specification of calculation level.

[0425] In specifying the transmitting station information, the transmitting station (interfering station) and receiving station to be subjected to interference evaluation are specified, and various specifications necessary for calculating the range of influence of interference caused by radio waves emitted from the transmitting station are made. Specifically, as shown in FIG. 36, the position of the transmitting station, wireless specifications, etc. are set. Note that here, the specific specification operation is performed by transitioning to another screen once, and the specified transmitting station and setting contents are displayed as transmitting station information on the execution condition specification screen hr. Note that the number of transmitting stations selected may be one or more.

[0426] When specifying the simple station placement study parameters, information about the receiving station is set, such as the height above ground of the receiving station at the evaluation point of each mesh (i.e., the center position of each mesh mentioned above), the minimum receiving sensitivity at that evaluation point, and antenna gain and feeder loss when a receiving antenna is placed at that evaluation point.

[0427] 36, the screen area rw, which is part of the specification of the simple station placement study specifications, displays images of two buttons: "Load road width" and "Save road width conditions." When the "Load road width" button is pressed, a message requesting the value of the average road width, which is information necessary for interference calculation, is sent to the map data processing device 100, and the value of the average road width is returned from the map data processing device 100. Furthermore, when the "Save road width conditions" button is pressed, the returned value of the average road width is saved, and the value of the average road width is automatically substituted into the variable of the propagation loss formula.

[0428] In the area specification, the aforementioned evaluation range e is specified. For example, the coordinates of the upper left and lower right of the rectangular evaluation range e are specified using latitude and longitude values. In addition, the spacing of the aforementioned dividing lines d, which leads to the specification of the size (unit area) of one mesh, is also specified in this area specification.

[0429] In the calculation level specification, it is possible to select a propagation loss formula to be used for interference evaluation. For example, the propagation loss formula can be the free space loss (square law) formula, the free space loss (square law) + ridge loss formula, or the formula described in Japanese Patent Application Laid-Open No. 2013-26884 (formulas (1) to (8) in the patent document). Furthermore, it is also possible to select the extended Hata formula, the formula specified in ITU-R Recommendation P.1411, or the like. If the value of the average road width is saved in the specification of the simplified base station placement study parameters described above, that value is automatically set as the variable of the selected propagation loss formula.

[0430] The interference evaluation system described above is configured so that the interference evaluation device 1 cooperates with the map data processing device 100 capable of calculating the average road width. However, since the device that performs the interference evaluation and the device that analyzes the map information are separate devices, the tools can be easily replaced depending on the purpose. In concrete terms, it is also easy to link the interference evaluation device 1 with another map data processing device that can extract information other than the average road width value from the map information. It is also easy to link the map data processing device 100 with another device that uses the average road width value for purposes other than interference evaluation.

[0431] According to the above-described embodiment, the map data processing device includes a map information acquisition unit, a range information acquisition unit, a range division unit, and a road width calculation unit. For example, the map data processing device is the map data processing device 100, 100a, or 100b in the embodiment, the map information acquisition unit is the map data acquisition unit 101 in the embodiment, the range information acquisition unit is the evaluation target range designation unit 103 in the embodiment, and the range division unit is the delimiter line interval designation unit 104 in the embodiment. The map information acquisition unit acquires map data indicating a map that can identify the positional relationship between the position of a road edge and the position of the road center. For example, the position of the road edge is road edge r in the embodiment, and the position of the road center is road center line c in the embodiment, and the map data is map information in the embodiment. The range information acquisition unit acquires information indicating the evaluation target range on the map. For example, the evaluation target range is evaluation target range e in the embodiment. The range division unit divides the evaluation target range into a grid by delimiter lines at a predetermined interval. For example, the delimiter lines are delimiter line d in the embodiment. The road width calculation unit calculates the average road width of the roads existing within the evaluation target range based on the positions of the edges and centers of the roads existing within each grid. For example, the grid is a mesh in the embodiment.

[0432] In the map data processing device described above, the road width calculation unit may include an intersection extraction unit, a distance measurement unit, an intersection road width calculation unit, and an average road width calculation unit. For example, the map data processing device is the map data processing device 100 or 100a in the embodiment, the intersection extraction unit is the intersection extraction unit 105 in the embodiment, the distance measurement unit is the distance measurement unit 106 in the embodiment, the intersection road width calculation unit is the road width calculation unit 107 in the embodiment, and the average road width calculation unit is the average road width calculation unit 109 in the embodiment. The intersection extraction unit extracts an intersection between a road center line indicating the center position of the road and a dividing line. For example, the intersection is intersection i in the embodiment. The distance measurement unit measures the shortest distance from the intersection to the edge of the road for each intersection. For example, the shortest distance is shortest distance L, or shortest distance L1 and shortest distance L2 in the embodiment. The intersection road width calculation unit calculates the road width of the road at the intersection position based on the shortest distance. The average road width calculation unit calculates the average road width based on the road width at each intersection.

[0433] In the above map data processing device, the distance measurement unit may measure the shortest distance from the intersection to the edge of one of the roads, and the road width calculation unit may calculate the road width by doubling the shortest distance. For example, the map data processing device is the map data processing device 100 in the embodiment, and the shortest distance is the shortest distance L in the embodiment.

[0434] In the above map data processing device, the distance measurement unit may measure a first shortest distance, which is the shortest distance from the intersection to the edge of the road on one side (corresponding to the above shortest distance L1), and a second shortest distance, which is the shortest distance from the intersection to the edge of the road on the other side (corresponding to the above shortest distance L2), and the road width calculation unit may calculate the road width by adding up the first shortest distance and the second shortest distance (the sum of the shortest distances L1 and L2). For example, the map data processing device is the map data processing device 100a in the embodiment, the first shortest distance is the shortest distance L1 in the embodiment, and the second shortest distance is the shortest distance L2 in the embodiment.

[0435] In the map data processing device described above, the road width calculation unit may include a unit area calculation unit, a road area determination unit, a road area counting unit, a road length counting unit, and an average road width calculation unit. For example, the unit area calculation unit is the unit area calculation unit 111 in the embodiment, the road area determination unit is the road area determination unit 112 in the embodiment, the road area counting unit is the road area counting unit 113 in the embodiment, the road length counting unit is the road length counting unit 115 in the embodiment, and the average road width calculation unit is the average road width calculation unit 109b in the embodiment. The unit area calculation unit calculates the unit area, which is the area of ​​a grid. The road area determination unit determines for each grid whether the grid is located in a road area on the map, and the road area counting unit counts the number of grids determined to be located in a road area. For example, a grid determined to be located in a road area is a mesh corresponding to a road in the embodiment. The road length counting unit calculates the sum of the lengths of road centerlines, which indicate the centers of roads existing within the evaluation range. The average road width calculation unit calculates the total area of ​​the grids determined to be located in the road area by multiplying the number of grids determined to be located in the road area by a unit area, and calculates the average road width by dividing the calculated total area of ​​the grids by the sum of the lengths of the road center lines.

[0436] Furthermore, according to the above-described embodiment, the interference evaluation system includes a map data processing device and an interference evaluation device. For example, the map data processing device is the map data processing device 100, 100a, or 100b in the embodiment, and the interference evaluation device is the interference evaluation device 1 in the embodiment. The map data processing device includes a map information acquisition unit, an area division unit, a road width calculation unit, and a road width output unit. For example, the road width calculation unit is the average road width information output unit 110 in the embodiment. The map information acquisition unit acquires map data representing a map that allows identification of the positional relationship between the positions of road edges and the positions of the road centers. The area information acquisition unit acquires information representing the evaluation target area on the map. The area division unit divides the evaluation target area into a grid by dividing lines at predetermined intervals. The road width calculation unit calculates the average road width of the roads present in the evaluation target area based on the positions of the road edges and the positions of the road centers present in each grid. The road width output unit outputs the value of the average road width of the roads to the interference evaluation device. The interference evaluation device includes a road width acquisition unit and a propagation loss calculation unit. For example, the road width acquisition unit is the calculation condition setting unit 16 in the embodiment, and the propagation loss calculation unit is the interference power calculation and pass / fail determination unit 18 in the embodiment. The road width acquisition unit acquires the value of the average road width of the road output from the map data processing device. The propagation loss calculation unit calculates the propagation loss by inputting the value of the average road width of the road into a variable of a calculation formula for calculating the propagation loss of radio waves propagating between wireless base stations. For example, the calculation formula for calculating the propagation loss of radio waves is the propagation loss formula (radio wave propagation formula) in the embodiment.

[0437] The map data processing device in each embodiment of the present invention and the interference evaluation device 1 in one embodiment of the present invention have been described above. Note that the map data processing device in each embodiment of the present invention and the interference evaluation device 1 in one embodiment of the present invention can also be realized by a computer and a program, and the program can be recorded on a recording medium or provided over a network.

[0438] The map data processing device in each of the above-described embodiments and the interference assessment device 1 in one embodiment of the present invention may be realized by a computer. In this case, a program for realizing the functions may be recorded on a computer-readable recording medium, and the program may be loaded into a computer system and executed. Note that the term "computer system" as used herein includes hardware such as an OS and peripheral devices. Furthermore, the term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into a computer system. Furthermore, the term "computer-readable recording medium" may also include devices that dynamically store programs for a short period of time, such as communication lines used when transmitting programs via networks such as the Internet or telephone lines, or devices that store programs for a fixed period of time, such as volatile memory within a computer system that serves as a server or client. The program may be for realizing some of the functions described above, or may be capable of realizing the functions in combination with a program already stored in the computer system, or may be realized using a programmable logic device such as an FPGA (Field Programmable Gate Array).

[0439] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention. [Explanation of symbols]

[0440] 1...Interference evaluation device, 10...Control unit, 11...Input setting, selection, and registration change instruction unit, 12...Interference method (menu) selection unit, 13...Station information input and registration unit, 14...Giving and interfered station selection unit, 15...History selection unit, 16...Calculation condition setting unit, 17...Calculation result display specification unit, 18...Interference power calculation and pass / fail judgment unit, 19...Graph display unit, 20...Memory unit, 30...Input / output unit, 100, 100a, 100b...Map data processing device, 101...Map data acquisition unit, 102...Road information extraction unit, 103...Evaluation target Range designation unit, 104, 104b...dividing line spacing designation unit, 105...intersection extraction unit, 106...distance measurement unit, 106a...two-way distance measurement unit, 107, 107a...road width calculation unit, 108...road width information storage unit, 109, 109b...average road width calculation unit, 110...average road width information output unit, 111...unit area calculation unit, 112...road area determination unit, 113...road area counting unit, 114...road length measurement unit, 115...road length counting unit, 202...history storage unit, 301...operation input unit, 302...display unit

Claims

1. a map information acquisition unit that acquires map data showing a map that can identify a positional relationship between a position of a road edge and a position of a center of the road; a range information acquisition unit that acquires information indicating an evaluation target range on the map; a range dividing unit that divides the evaluation target range into a grid by dividing lines at predetermined intervals; a road width calculation unit that calculates an average road width of the roads that exist within the evaluation range based on the positions of the edges of the roads and the positions of the centers of the roads that exist within each grid; A map data processing device comprising:

2. The road width calculation unit an intersection extraction unit that extracts intersections between a road center line indicating the center position of the road and a dividing line; a distance measurement unit that measures the shortest distance from each intersection to the edge of the road; an intersection road width calculation unit that calculates a road width of the road at the intersection based on the shortest distance; an average road width calculation unit that calculates an average road width based on the road width for each intersection; Equipped with The map data processing device according to claim 1 .

3. the distance measurement unit measures the shortest distance from the intersection to a position of an edge of the road on one side; The road width calculation unit calculates the road width by doubling the shortest distance. The map data processing device according to claim 2 .

4. the distance measurement unit measures a first shortest distance, which is the shortest distance from the intersection to a position of an edge of the road on one side, and a second shortest distance, which is the shortest distance from the intersection to a position of an edge of the road on the other side; The road width calculation unit calculates the road width by adding up the first shortest distance and the second shortest distance. The map data processing device according to claim 2 .

5. The road width calculation unit a unit area calculation unit that calculates a unit area, which is the area of ​​the grid; a road area determination unit that determines, for each grid, whether or not the grid is located in an area of ​​the road in the map; a road area counting unit that counts the number of grids that are determined to be located in the road area; a road length calculation unit that calculates the total length of road centerlines that indicate the center positions of the roads that exist within the evaluation range; an average road width calculation unit that calculates a total area of ​​the grids determined to be located in the road area by multiplying the unit area by the number of the grids determined to be located in the road area, and calculates the average road width by dividing the calculated total area of ​​the grids by the sum of the lengths of the road center lines; The map data processing device according to claim 1 , further comprising:

6. An interference assessment system having a map data processing device and an interference assessment device, The map data processing device includes: a map information acquisition unit that acquires map data showing a map that can identify a positional relationship between a position of a road edge and a position of a center of the road; a range information acquisition unit that acquires information indicating an evaluation target range on the map; a range dividing unit that divides the evaluation target range into a grid by dividing lines at predetermined intervals; a road width calculation unit that calculates an average road width of the roads that exist within the evaluation range based on the positions of the edges of the roads and the positions of the centers of the roads that exist within each grid; a road width output unit that outputs the average road width value of the road to the interference assessment device; Equipped with The interference assessment device a road width acquisition unit that acquires the average road width value of the road output from the map data processing device; a propagation loss calculation unit that calculates the propagation loss by inputting the value of the average road width of the road into a variable of a calculation formula that calculates the propagation loss of radio waves propagating between wireless base stations; Equipped with Interference assessment system.

7. A computer-implemented map data processing method, comprising: a map information acquisition step of acquiring map data showing a map that can identify a positional relationship between a position of a road edge and a position of a center of the road; a range information acquisition step of acquiring information indicating an evaluation target range on the map; a range dividing step of dividing the evaluation target range into a grid by dividing lines at predetermined intervals; a road width calculation step of calculating an average road width of the roads existing within the evaluation range based on the positions of the edges of the roads existing within each grid and the positions of the centers of the roads; A map data processing method comprising:

8. A program that causes a computer to function as the map data processing device according to any one of claims 1 to 5.

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