Map information creation device, map display system, and map information creation program

Abstract

To provide a map information creation device capable of creating map information, for causing a detailed map to be displayed within a desired processing load.SOLUTION: A server 10, which is a map information creation device, includes: a communication unit 11 that receives, from a terminal, a map display request in which at least one of a display area of infrastructure facilities on a map and a scale is designated; and a map information generation unit 13 that creates map information for displaying a thinned map in which some of features included in the map are thinned based on the map display request. The map information generation unit 13 creates the map information so that the display processing load when the terminal displays the thinned map is equal to or less than a specific value. The communication unit 11 transmits the map information to the terminal.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a map information creation device, a map display system, and a map information creation program that create information on a map to be displayed. [Background technology]

[0002] In infrastructure facilities such as power system facilities, facilities are managed by displaying utility poles and other features on a map. Systems for managing such infrastructure facilities use client terminals such as PCs (Personal Computers) and tablets. These client terminals are operated by facility work supervisors and on-site workers to access a server and display features on a map based on map information sent from the server.

[0003] For example, when a client terminal displays a system diagram used in the electric power industry, it displays various facilities managed by electric power companies, such as utility poles and electric wires. However, when a client terminal attempts to display a wide-area system diagram on the screen, it needs to display a large number of facilities, which can take a long time to process and cause the user to wait. For this reason, when a map is displayed on a client terminal, it is desirable to display a detailed map with a small processing load.

[0004] The graphic creation and display device described in Patent Document 1 quickly displays small-scale maps by thinning out, from the entire graphic data, graphic data that corresponds to graphic type data set for each scale. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-095974 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the technology of Patent Document 1 mentioned above has a problem in that as the amount of graphic data increases, the processing load when displaying a map increases, and it is not always possible to display a detailed map within the desired processing load.

[0007] The present disclosure has been made in consideration of the above, and aims to provide a map information creation device that can create map information for displaying a detailed map within a desired processing load. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the map information creation device of the present disclosure includes a communication unit that receives from a terminal a map display request in which at least one of a display area and a scale of an infrastructure facility on a map is specified, and a map information generation unit that creates map information for displaying a thinned map in which some of the features included in the map are thinned out, based on the map display request. The map information generation unit: Based on the map display request, information on the features included in the display area is obtained as range feature information from a first database that stores information on the features, and thinning information corresponding to the features included in the range feature information among the features is obtained as request thinning information from a second database that stores thinning information that specifies whether or not each of the features is to be displayed on the thinned map. Using the range feature information and the request thinning information, The map information is created, and the communication unit transmits the map information to the terminal. Effect of the Invention

[0009] The map information creation device according to the present disclosure provides an effect of being able to create map information for displaying a detailed map within a desired processing load. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a configuration of a map display system according to an embodiment; [Diagram 2] FIG. 1 is a diagram for explaining an overview of a thinning process performed by a server according to an embodiment; [Diagram 3] FIG. 1 is a diagram showing a configuration of a server included in a map display system according to an embodiment; [Figure 4] FIG. 1 is a diagram showing a configuration of a client terminal included in a map display system according to an embodiment; [Diagram 5]FIG. 1 is a diagram for explaining a registration process of update thinning information registered by a map display system according to an embodiment; [Figure 6] 1 is a flowchart showing a registration process procedure of update thinning information registered by a map display system according to an embodiment; [Figure 7] FIG. 1 is a diagram for explaining a map display process of a map displayed by a map display system according to an embodiment; [Figure 8] 1 is a flowchart showing a map display process procedure of a map displayed by a map display system according to an embodiment; [Figure 9] A flowchart showing a registration process procedure of a thinned feature registered by a server according to an embodiment. [Figure 10] FIG. 1 is a diagram for explaining a first process performed by a server according to an embodiment when making a thinning decision; [Figure 11] FIG. 11 is a diagram for explaining a second process performed by the server according to the embodiment when making a thinning decision; [Figure 12] FIG. 11 is a diagram for explaining a third process performed by the server according to the embodiment when making a thinning decision; [Figure 13] FIG. 11 is a diagram for explaining a fourth process performed by the server according to the embodiment to perform thinning determination; [Figure 14] FIG. 11 is a diagram for explaining a fifth process performed by the server according to the embodiment to perform thinning determination; [Figure 15] FIG. 1 is a diagram for explaining a map area that is set when the server according to the embodiment creates update thinning information; [Figure 16] FIG. 1 is a diagram illustrating a configuration example of a processing circuit included in a server according to an embodiment when the processing circuit is realized by a processor and a memory; [Figure 17] FIG. 1 is a diagram illustrating an example of a processing circuit in a server according to an embodiment, in which the processing circuit is configured with dedicated hardware; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A map information creation device, a map display system, and a map information creation program according to embodiments of the present disclosure will be described below in detail with reference to the drawings.

[0012] Embodiment 1 is a diagram showing a configuration of a map display system according to an embodiment. The map display system 1 includes a server 10 which is a map information creation device, one or more client terminals 20 which are map display devices, a feature DB (DataBase) 60, and a thinning information DB 40. The feature DB 60 is a first database, and the thinning information DB 40 is a second database.

[0013] The map display system 1 is a system that displays a map of infrastructure facilities such as power system facilities on the client terminal 20. The map display system 1 displays a map as detailed as possible while keeping the processing load when displaying the map below a specific value by thinning out specific features according to the scale, display area, etc. In other words, the map display system 1 reduces the processing load when displaying a wide-area system map and improves the user experience.

[0014] The server 10 is capable of communicating with the client terminal 20 via a communication network such as the Internet. The server 10 is also connected to a feature DB 60 and a thinning information DB 40. At least one of the feature DB 60 and the thinning information DB 40 may be located within the server 10.

[0015] The server 10 is a web server such as a geographic information system (GIS) server. The server 10 registers edited feature information (feature editing information 31, described later) sent from the client terminal 20 in the feature DB 60. The server 10 also acquires feature information (updated feature information 32, described later) corresponding to the feature editing information 31 from the feature DB 60. The server 10 creates information indicating which features on the map should be thinned out (updated thinning information 33, described later) based on the updated feature information 32, and registers the information in the thinning information DB 40.

[0016] The features in the embodiment include utility poles, transformers, switches, and electric wires. Of these features, utility poles, transformers, and switches are point features, and electric wires are line features. In other words, point features include at least one of utility poles, transformers, and switches, and line features include electric wires. Line features are features that connect point features together.

[0017] Furthermore, when the server 10 receives a request to display a map from the client terminal 20 (a map display request 51, described later), the server 10 creates map information (map information 56, described later) corresponding to the map display request 51. The server 10 creates the map information 56 using the feature DB 60 and the thinning information DB 40.

[0018] The server 10 of the embodiment creates map information 56 based on the priority of thinning out features to display as much detailed information as possible while keeping the processing load when displaying a map within a desired processing load. The server 10 reduces the processing load when displaying a map by thinning out specific features based on the priority of thinning out features. The server 10 transmits the created map information 56 to the client terminal 20. The client terminal 20 is a PC, a tablet, a smartphone, or the like. The client terminal 20 displays a map 25 corresponding to the map information 56.

[0019] The map 25 displayed by the client terminal 20 is a map corresponding to the map display request 51. In the map 25, point features are shown as dots, and line features are shown as lines. In the map 25 displayed by the client terminal 20, some of the features have been thinned out. That is, in the map 25, certain point features are omitted from the illustration, and certain line features are simplified. In this way, the map 25 is a thinned map in which some of the features included in the map before thinning (hereinafter referred to as the original map) have been thinned out. The original map is a map (an unthinned map) in which all features are arranged on a background map described later.

[0020] When a user edits information about features included in the original map of the map 25 using the client terminal 20, the client terminal 20 creates feature editing information 31 corresponding to the editing result and transmits it to the server 10. As a result, the server 10 registers the feature editing information 31 in the feature DB 60.

[0021] The client terminal 20 stores a map (background map) that is the background of the original map, and creates feature editing information 31 in which coordinates on this background map are associated with information on features displayed at these coordinates. The background map is a map from which all features have been deleted from the original map. Positions on the background map correspond to positions on the Earth (latitude and longitude). In other words, the background map is a map in which at least latitude and longitude are specified. The background map may include roads, buildings, mountains, rivers, and the like. The user specifies a position (coordinates) on the background map and then edits information on the feature at this position. The coordinates on the background map, the coordinates on the original map, and the coordinates on the thinned map are the same coordinates.

[0022] The feature DB 60 stores overall feature information (overall feature information 81 described later), which is feature information on the entire feature, and the original map. The feature DB 60 may store a background map instead of the original map. The overall feature information 81 is updated by the feature editing information 31. That is, the server 10 updates the portion of the overall feature information 81 stored in the feature DB 60 that corresponds to the feature editing information 31 by the feature editing information 31.

[0023] When the server 10 registers the feature editing information 31, it acquires updated feature information 32 corresponding to this feature editing information 31, and creates updated thinning information 33 using the updated feature information 32. Specifically, the server 10 divides the map 25 into a plurality of map areas, and creates updated thinning information 33 for each map area. The server 10 creates updated thinning information 33 for each map area for all scales that can be set on the map 25. Note that when only a specific map area in the map 25 is updated, the server 10 creates updated thinning information 33 for the updated map area. The server 10 registers the updated thinning information 33 in the thinning information DB 40.

[0024] The thinning information DB 40 stores overall thinning information (overall thinning information 82 described later) that is thinning information for all features. The overall thinning information 82 includes a list of identification information (feature identification information 54 described later) of the features to be thinned. The overall thinning information 82 is updated by the updated thinning information 33. That is, the server 10 updates the portion of the overall thinning information 82 stored in the thinning information DB 40 that corresponds to the updated thinning information 33 with the updated thinning information 33.

[0025] Furthermore, when a map display request 51 is sent from the client terminal 20 , the server 10 creates a thinned map 25 using the feature DB 60 and the thinned information DB 40 , and transmits the thinned map 25 to the client terminal 20 .

[0026] The client terminal 20 receives the map 25 corresponding to the map display request 51 from the server 10 and displays it. This allows the map display system 1 to display a map as detailed as possible on the client terminal 20 while suppressing the processing load of the display to a specific value or less.

[0027] Here, an overview of the thinning process by the server 10 will be described. Fig. 2 is a diagram for explaining an overview of the thinning process by the server according to the embodiment. The server 10 creates maps 41 to 46 by thinning out specific features according to the scale of the map on which the features are displayed, the size of the display area, and the like.

[0028] Map 41 is a part of the original map before thinning, and includes point features 70 and line features 80. Map 41 shows the arrangement of point features 70 and line features 80. Server 10 creates map 46 by thinning out specific features from map 41 so that the processing load for display is equal to or less than a specific value and as many features as possible can be displayed. In this case, server 10 determines which features to thin out based on the thinning priority of each feature. That is, server 10 thins out features in order of highest thinning priority until the processing load for display is equal to or less than a specific value.

[0029] The priority of thinning is high when features can be thinned while maintaining the overview of the original map. The overview of the original map is easily maintained by retaining branching points of line features 80, terminal points of point features 70, etc., contained in the original map. Therefore, branching points of line features 80, terminal points of point features 70, etc., contained in the original map have a low priority for thinning.

[0030] The server 10 creates a map 46 by thinning out specific point features 70 and line features 80 from the map 41 and simplifying the specific line features 80. When simplifying the specific line features 80, the server 10 reconstructs the line features 80 so as to maintain the connection relationships between the point features 70 that were not thinned out. This enables the server 10 to display on the client terminal 20 a number of features that correspond to the processing load of the display while maintaining the overview of the original map. Information indicating which features on the map 41 are to be thinned out is updated thinning information 33, which is created by the server 10.

[0031] 3 is a diagram showing a configuration of a server included in the map display system according to the embodiment. The server 10 includes a communication unit 11, a registration unit 12, and a map information generation unit 13.

[0032] The communication unit 11 executes communication with the client terminal 20. When the communication unit 11 receives feature editing information 31 from the client terminal 20, the communication unit 11 sends the received feature editing information 31 to the registration unit 12.

[0033] The feature editing information 31 is information that indicates the editing contents of a feature. In other words, the feature editing information 31 indicates the editing result of the feature information. The feature editing information 31 includes feature identification information 54 for identifying the feature, the position of the feature changed by the user, the attribute of the feature changed by the user, etc. The client terminal 20 is capable of receiving an instruction to create the feature editing information 31 (an instruction to edit the feature information) from the user while displaying the original map or the map 25.

[0034] The client terminal 20 adds features, deletes features, changes the location of features, changes the attributes of features, etc., in accordance with editing instructions from the user, to create feature editing information 31. The attributes of features include, for example, information indicating whether a feature is normal or abnormal, whether there has been a power outage at the feature, the date the feature was installed, the date the feature was inspected, and the results of inspection of the feature.

[0035] Furthermore, when the communication unit 11 receives a map display request 51 from the client terminal 20, it sends the received map display request 51 to the registration unit 12. The map display request 51 is information for requesting map information 56 used to display the map 25. The map display request 51 includes a scale (scale information 85 described later) and an area (display area) requested to be displayed as the map 25. That is, the client terminal 20 transmits to the server 10 a map display request 51 indicating the scale and area specified by the user. Note that once one of the scale and area requested to be displayed as the map 25 is determined, the other can be inferred, so it is sufficient that the map display request 51 includes at least one of the scale and area requested to be displayed as the map 25.

[0036] The user specifies the center coordinates and scale of the area that the user wants to display as map 25 by having the original map displayed on client terminal 20 with the area and scale that the user wants to display. The center coordinates of the area of ​​the original map that the user has displayed on client terminal 20 are the center coordinates of the area that the user wants to display as map 25. In addition, the scale of the original map that the user has displayed on client terminal 20 is the scale of map 25 that the user wants to display.

[0037] The feature editing information 31 or the map display request 51 may include information (layer information) specifying the type of feature to be displayed, or information specifying the attributes of the feature to be displayed. The layer information is information specifying the type of feature, such as a utility pole, electric wire, switch, or transformer. The layer information may specify the type of feature to be displayed, or may specify the type of feature not to be displayed. The information specifying the attributes of the feature to be displayed may specify, for example, an abnormal feature, a normal feature, or the like.

[0038] Furthermore, the communication unit 11 transmits the map information 56 created by the map information generation unit 13 to the terminal that transmitted the map display request 51, i.e., the client terminal 20. The map information 56 is information for displaying the map 25 on which the features have been thinned out.

[0039] The registration unit 12 registers the feature editing information 31 in the feature DB 60. Specifically, the registration unit 12 transmits an instruction to update the overall feature information 81, which is information about the entire feature, to the feature DB 60, based on the changed parts of the feature indicated by the feature editing information 31. This updates the overall feature information 81 stored in the feature DB 60. The overall feature information 81 includes position information (coordinates on the original map) of features such as utility poles, electric wires, switches, and transformers, feature attribute information, feature identification information 54, and the like. The feature identification information 54 is information for identifying features, and unique information is assigned to each feature.

[0040] The registration unit 12 obtains updated object information 32 corresponding to the object editing information 31 from the object DB 60. That is, the registration unit 12 extracts updated object information 32 indicating information on updated objects from the overall object information 81. The updated object information 32 is part of the object information included in the overall object information 81. Therefore, the updated object information 32 includes position information of objects such as utility poles, electric wires, switches, and transformers, object attribute information, object identification information 54, and the like.

[0041] The registration unit 12 creates the update thinning information 33 based on the updated feature information 32. The registration unit 12 registers the created update thinning information 33 in the thinning information DB 40. The update thinning information 33 is information indicating which features are to be thinned (not displayed on the screen) for each scale. That is, the update thinning information 33 indicates whether each feature is to be thinned for each scale. In the update thinning information 33, for example, a list of identification information of features to be thinned is stored for each scale and each area. The registration unit 12 creates the update thinning information 33 in which whether or not to display a feature is set for each feature and for each scale so that the processing load of the display is equal to or less than a specific value. Note that in this embodiment, a case where the scale is changed stepwise will be described, but the scale may be changed continuously. That is, an arbitrary scale may be set for the map 25. When the scale is changed continuously, the server 10 determines the features to be thinned while changing the scale. During this determination process, the server 10 determines up to what scale each feature should be displayed, and when determining whether or not to display it, it determines whether each feature is a target for thinning out depending on whether the current scale requested is larger than the scale at which it should be displayed. This allows the server 10 to determine whether each feature is a target for thinning out for each scale, even when the scale is changed continuously.

[0042] The map information generating unit 13 creates a request to acquire feature information (range feature acquisition request 52, described later) based on the map display request 51. The range feature acquisition request 52 is instruction information that requests feature information of the area specified in the map display request 51 (range feature information 53, described later).

[0043] The range feature information 53 is information about features located in the area specified in the range feature acquisition request 52. The range feature information 53 is part of the feature information included in the overall feature information 81. Therefore, the range feature information 53 includes position information (coordinates on the original map) of features such as utility poles, electric wires, switches, and transformers, feature attribute information, feature identification information 54, and the like.

[0044] The map information generating unit 13 sends the range feature acquisition request 52 to the feature DB 60 , and reads out the range feature information 53 corresponding to the range feature acquisition request 52 from the overall feature information 81 stored in the feature DB 60 .

[0045] The map information generation unit 13 acquires thinning information (request thinning information 55 described later) corresponding to the map display request 51 from the thinning information DB 40 based on the scale information 85 included in the map display request 51, the feature identification information 54 included in the range feature information 53 acquired from the feature DB 60, and the original map acquired from the feature DB 60.

[0046] Feature identification information 54 included in range feature information 53 is identification information of features located in the area specified in map display request 51. Request thinning information 55 acquired by map information generation unit 13 from thinning information DB 40 is thinning information corresponding to scale information 85 and the area included in map display request 51. Scale information 85 is information on the scale specified in map display request 51, and client terminal 20 displays map 25 at the scale indicated by scale information 85. Request thinning information 55 includes a list of feature identification information 54 of features to be thinned.

[0047] The map information generation unit 13 creates map information 56 corresponding to the map 25 using the range feature information 53, the request thinning information 55, and the original map. The map information 56 includes feature position information, feature attribute information, feature identification information 54, and the like. The map information generation unit 13 creates map information 56 corresponding to the map 25 by thinning out features set to be thinned in the request thinning information 55 from among the features in the range feature information 53. That is, the map information generation unit 13 thins out point features 70 and line features 80 using the request thinning information 55, and reconstructs line features 80 at locations where the point features 70 have been thinned out. In this case, the map information generation unit 13 reconstructs the line features 80 so that the connection relationships between the point features 70 that have not been thinned out are maintained. In other words, the map information generation unit 13 reconstructs the line features 80 so that point features 70 that were connected via one or more line features 80 in the original map are still connected via the line features 80 after the reconstruction.

[0048] 4 is a diagram showing a configuration of a client terminal included in the map display system according to the embodiment. The client terminal 20 includes an input unit 21, an editing unit 22, a communication unit 23, and a display unit 24.

[0049] The input unit 21 accepts instructions from the user and sends them to the editing unit 22. The instructions that the input unit 21 accepts from the user include an instruction to create feature editing information 31 (an instruction to edit features), an instruction to transmit feature editing information 31, an instruction to create a map display request 51 (an instruction to display the map 25), an instruction to transmit the map display request 51, and the like.

[0050] When the editing unit 22 receives an instruction to create feature editing information 31 from the input unit 21, it edits the information of the features in accordance with the instruction to create the feature editing information 31. The editing unit 22 creates the feature editing information 31 while displaying the original map of the map 25, the feature editing information 31, etc. on the display unit 24.

[0051] Furthermore, when the editing unit 22 receives an instruction to create a map display request 51 from the input unit 21, the editing unit 22 creates the map display request 51 according to the instruction. The editing unit 22 creates the map display request 51 while displaying the map display request 51 on the display unit 24.

[0052] When the editing unit 22 receives an instruction to send the feature editing information 31 from the input unit 21, it sends the created feature editing information 31 to the communication unit 23. In addition, when the editing unit 22 receives an instruction to send a map display request 51 from the input unit 21, it sends the created map display request 51 to the communication unit 23.

[0053] The communication unit 23 transmits the feature editing information 31, the map display request 51, and the like to the server 10. The communication unit 23 also receives map information 56 from the server 10 and sends the received map information 56 to the display unit 24.

[0054] The display unit 24 is equipped with a display device such as a liquid crystal monitor, and displays the map 25 corresponding to the map information 56. Furthermore, the display unit 24 displays the original map of the map 25, the feature editing information 31, the map display request 51, etc., according to instructions from the editing unit 22.

[0055] Fig. 5 is a diagram for explaining a registration process of the update thinning information registered by the map display system according to the embodiment, Fig. 6 is a flowchart showing a registration process procedure of the update thinning information registered by the map display system according to the embodiment.

[0056] The editing unit 22 of the client terminal 20 edits the information of the feature in accordance with an operation from the user. The communication unit 23 of the client terminal 20 transmits feature editing information 31 indicating the result of editing the feature to the server 10 (step ST1).

[0057] The communication unit 11 of the server 10 receives the feature editing information 31. The registration unit 12 of the server 10 registers the feature editing information 31 in the feature DB 60 (step ST2). Specifically, the registration unit 12 of the server 10 registers the feature editing information 31 in the overall feature information 81 by transmitting the feature editing information 31 to the feature DB 60. That is, the registration unit 12 of the server 10 updates the overall feature information 81 in the feature DB 60 based on the feature editing information 31.

[0058] The registration unit 12 of the server 10 acquires the updated feature information 32 from the feature DB 60 (step ST3). In this case, the registration unit 12 of the server 10 acquires the updated feature information 32 including not only the information of the changed feature but also the information of the area in which the changed feature exists. The updated feature information 32 acquired by the registration unit 12 of the server 10 from the feature DB 60 corresponds to the feature editing information 31 registered in the feature DB 60.

[0059] The registration unit 12 of the server 10 determines thinned features, which are features to be thinned, based on the acquired updated feature information 32 (step ST4). The registration unit 12 of the server 10 creates updated thinning information 33 corresponding to the determined thinned features. In this way, the registration unit 12 of the server 10 acquires updated feature information 32 including information on the changed features and information on the area in which the changed features exist, and recalculates new thinned features. The registration unit 12 of the server 10 registers the created updated thinning information 33 in the thinning information DB 40 (step ST5).

[0060] The registration unit 12 may execute the aggregation process (processing of sending the feature editing information 31 to the feature DB 60) by batch processing. In this case, the feature editing information 31 of the newly added feature is not sent to the feature DB 60 until batch processing. Therefore, the newly added feature is displayed as it is on the map 25 until batch processing. The registration unit 12 may also execute the update process of the updated thinning information 33 by batch processing (processing of registering the updated thinning information 33 in the thinning information DB 40). In this case, the registration unit 12 does not obtain the updated feature information 32 corresponding to the feature editing information 31 of the newly added feature from the feature DB 60 until batch processing. The registration unit 12 reads out the updated feature information 32 collectively during batch processing and updates the updated thinning information 33 collectively.

[0061] Fig. 7 is a diagram for explaining a map display process of a map displayed by the map display system according to the embodiment, and Fig. 8 is a flowchart showing a map display process procedure of a map displayed by the map display system according to the embodiment.

[0062] In response to an operation from a user, the editing unit 22 of the client terminal 20 creates a map display request 51. This map display request 51 includes scale information 85, information indicating a specific area (area to be displayed) within the map 25, and the like.

[0063] The communication unit 23 of the client terminal 20 transmits a map display request 51 to the server 10 (step ST11). The map information generation unit 13 of the server 10 creates an area feature acquisition request 52 based on the map display request 51. The map information generation unit 13 of the server 10 transmits the area feature acquisition request 52 to the feature DB 60 (step ST12).

[0064] The map information generation unit 13 of the server 10 sends the range feature acquisition request 52 to the feature DB 60, and acquires the range feature information 53 corresponding to the range feature acquisition request 52 from the overall feature information 81 stored in the feature DB 60 (step ST13).

[0065] The map information generating unit 13 of the server 10 transmits the scale information 85 included in the map display request 51 and the feature identification information 54 included in the area feature information 53 to the thinning information DB 40 (step ST14). As a result, the map information generating unit 13 of the server 10 acquires the request thinning information 55 corresponding to the scale information 85 and the feature identification information 54 from the overall thinning information 82 stored in the thinning information DB 40 (step ST15).

[0066] The map information generating unit 13 of the server 10 creates map information 56 corresponding to the map 25 using the area feature information 53, the request thinning information 55, and the original map (step ST16). The communication unit 11 of the server 10 transmits the map information 56 to the client terminal 20 (step ST17). The communication unit 23 of the client terminal 20 receives the map information 56. Then, the display unit 24 of the client terminal 20 displays the map 25 corresponding to the map information 56 (step ST18).

[0067] The processes by the server 10 described with reference to FIGS. 5 and 6 and the processes by the server 10 described with reference to FIGS. 7 and 8 may be executed by different servers 10.

[0068] Here, a description will be given of a registration process of the updated thinned information 33 by the registration unit 12 of the server 10. Fig. 9 is a flowchart showing a registration process procedure of thinned features registered by the server according to the embodiment.

[0069] The registration unit 12 of the server 10 acquires the updated feature information 32 corresponding to the area specified in the feature editing information 31, i.e., the updated area, from the feature DB 60 (step ST21). The updated area specified in the map display request 51 is the area in which the information of the features has been updated.

[0070] The registration unit 12 of the server 10 derives a thinning priority for each feature included in the updated feature information 32 (step ST22). The registration unit 12 derives a priority for each feature for which priority is to be derived (hereinafter, may be referred to as a target point feature). The registration unit 12 derives a thinning priority for each target point feature based on the following priority derivation elements (1) to (5). (1) Attributes of target points (2) Whether the target point feature is a branch point of a line feature 80 (3) Whether the target point feature is an end point or not (4) Distance from the branch point of the target feature (5) The distance from the line segment connecting the two adjacent points 70 to the target point

[0071] For example, when the normal state of a utility pole is set as an attribute of a feature, the registration unit 12 increases the priority of thinning out for this feature (target point feature). The registration unit 12 may increase the priority of thinning out when an abnormal state of a utility pole is set. The registration unit 12 may also increase the priority of thinning out when there is a power outage at the feature, or may increase the priority of thinning out when there is no power outage at the feature. The user sets in the server 10 which attribute to increase the priority of.

[0072] Furthermore, the registration unit 12 increases the priority of thinning when the target point feature is not a branch point. Furthermore, the registration unit 12 increases the priority of thinning when the target point feature is not an end point. Furthermore, the registration unit 12 increases the priority of thinning when the distance from the target point feature to the branch point is short. In this case, the distance from the branch point may be a straight line distance or may be the total distance when tracing the line features 80 in order.

[0073] The registration unit 12 also extracts point features 70 located on both sides of the target point feature. The extracted point features 70 are point features 70 connected to the target point feature via a line feature 80. The registration unit 12 increases the priority of thinning when the distance from the line segment connecting the two extracted point features 70 to the target point feature is shorter than a specific value.

[0074] The registration unit 12 assigns weights to each of the above-mentioned (1) to (5) and sets a thinning priority for each feature. The weights of (1) to (5) are set in the server 10 by the user.

[0075] The registration unit 12 determines the feature to be thinned out based on the priority set for each point feature 70 (step ST23). That is, the registration unit 12 sets priorities for thinning out for all features, and sets the point features 70 with the highest priority for thinning out as the features to be thinned out in descending order.

[0076] For example, the registration unit 12 assigns a score indicating a priority to each point feature 70 based on the priority set for each point feature 70. Then, the registration unit 12 sets each point feature 70 as a feature to be thinned out in descending order of score.

[0077] When the registration unit 12 thins out the point feature 70 at the end point, it sets the line feature 80 connected to the thinned point feature 70 as the feature to be thinned out. The registration unit 12 executes the thinning setting for the point features 70 and the line features 80 until the number of the point features 70 and the line features 80 becomes equal to or less than a specific value when the client terminal 20 displays the map 25.

[0078] The display processing load when the map 25 is displayed is calculated by the registration unit 12 based on the number of point features 70 and the number of line features 80. Note that the registration unit 12 may calculate the display processing load based on the number of point features 70 and the number of line features 80 when the map information generation unit 13 reconstructs the line features 80.

[0079] The specific value to be compared with the processing load may be registered in advance in the server 10, or a specific value requested by the client terminal 20 may be applied.

[0080] The registration unit 12 may thin out the point features 70 and reconstruct the line features 80 so that the display processing time when the client terminal 20 displays the map 25 is within a specific time. In this case, the registration unit 12 reconstructs the features based on the display processing capacity of the client terminal 20 so that the display processing time when the map 25 is displayed is within a specific time.

[0081] The registration unit 12 registers the determined thinned feature in the thinning information DB 40 (step ST24). That is, the registration unit 12 registers updated thinning information 33 indicating whether or not each feature is a target for thinning in the thinning information DB 40. Specifically, the registration unit 12 creates updated thinning information 33 in which scale information 85, feature identification information 54 of the feature, and information indicating whether or not the feature is a target for thinning are associated with each other, and registers the updated thinning information 33 in the thinning information DB 40.

[0082] The thinning information DB40 stores overall thinning information 82 in which, for each scale information 85, feature identification information 54 is associated with information indicating whether the feature is a target for thinning, and updates the overall thinning information 82 using updated thinning information 33.

[0083] The registration unit 12 judges whether or not thinned features have been determined for all update regions (step ST25). If thinned features have not been determined for all update regions (step ST25, No), the registration unit 12 returns to the process of step ST21 and executes the processes of steps ST21 to ST24. If thinned features have been determined for all update regions (step ST25, Yes), the registration unit 12 ends the registration process of the update thinning information 33.

[0084] When the original map of map 25 is created initially, the entire original map becomes the update area. In this case, registration unit 12 creates update thinning information 33 for each scale information 85 for all areas of the original map and registers it in thinning information DB 40. At this time, the update thinning information 33 registered in thinning information DB 40 becomes overall thinning information 82, and when map 25 is updated thereafter, overall thinning information 82 is updated using the update thinning information 33.

[0085] In the embodiment, the case has been described where the registration unit 12 assigns weights to each of the above (1) to (5) and sets a priority for thinning out for each feature, but the registration unit 12 may thin out features in order according to the above (1) to (5). In this case, the registration unit 12 thins out features in order until the processing load for display falls below a specific value. The thinning out process by the registration unit 12 in this case will be described below.

[0086] The registration unit 12 creates a map 46 using the map 41 shown in FIG. 2 as the original map by executing the first process to the fifth process included in the thinning process in order. FIG. 10 is a diagram for explaining the first process performed when the server according to the embodiment makes a thinning decision. The registration unit 12 of the server 10 creates a map 42 shown in FIG. 10 from the map 41 shown in FIG. 2. Specifically, the registration unit 12 sets an arbitrary feature on the map 41 as a reference node. FIG. 10 shows a case where a point feature 71A is set as the reference node.

[0087] The registration unit 12 extracts a path from the point feature 71A, which is the reference node, to the farthest node (point feature 72). The point feature 72 farthest from the point feature 71A is the point feature with the largest number of line features 80 connections when tracing line features 80 from the point feature 71A. In other words, the point feature 72 connected to the point feature 71A via the largest number of line features 80 is the point feature 72 farthest from the point feature 71A.

[0088] The registration unit 12 extracts a point feature 73 included in the path from the point feature 71A to the point feature 72. The first process is a process in which the registration unit 12 sets the point feature 71A as a reference node and extracts the point features 72 and 73. Fig. 10 shows a state in which the point feature 71A is set and the point features 72 and 73 are extracted.

[0089] Fig. 11 is a diagram for explaining a second process performed by the server according to the embodiment when making a thinning decision. The registration unit 12 creates a map 43 shown in Fig. 11 from the map 42 shown in Fig. 10. Specifically, the registration unit 12 extracts, from among the point features 73, point features 73 that are branching points of line features 80. A point feature 73 that is a branching point of line features 80 is a point feature to which three or more line features 80 are connected.

[0090] The registration unit 12 extracts a point feature 74 that is a terminating point feature and has a shortest distance from the point feature 73 less than or equal to a reference value L, from among the point features 70 connected to a point feature 73 that is a branch point of a line feature 80. Note that the distance from the point feature 73 may be the total distance of the route when the line features 80 are traced in order.

[0091] The second process is a process in which the registration unit 12 extracts the point feature 73 that is a branch point and a process in which the registration unit 12 extracts the point feature 74. Fig. 11 shows a state in which the point feature 71A is set and the point features 72 to 74 are extracted.

[0092] FIG. 12 is a diagram for explaining a third process performed by the server according to the embodiment when making a thinning decision. The registration unit 12 creates a map 44 shown in FIG. 12 from the map 43 shown in FIG. 11. Specifically, the registration unit 12 deletes the point feature 74 extracted in the second process by setting it as a feature to be thinned. The registration unit 12 also deletes the line feature 80 connected to the deleted point feature 74 by setting it as a feature to be thinned. The line feature 80 connected to the point feature 74 is a line feature with one end connected to the point feature 73 and with the other end to which no point feature is connected due to the deletion of the point feature 74. The third process is a process performed by the registration unit 12 to delete the point feature 74 extracted in the second process by setting it as a feature to be thinned and to delete the line feature 80 connected to the point feature 74 by setting it as a feature to be thinned.

[0093] Furthermore, the registration unit 12 extracts edges that are connected to the point feature 73 that is a branch point of the line feature 80 and that extend farther from the point feature 73 than the reference value L. In other words, the registration unit 12 extracts edges that extend from the path from the point feature 71A to the point feature 72 and from which the point feature 74 has not been deleted.

[0094] The registration unit 12 executes the first process to the third process on the extracted branch. That is, the registration unit 12 sets the point feature 73, which is one end of the extracted branch, as the point feature 71B, which is a new reference node. Fig. 12 shows a case where the point feature 73, which is located on the path from the point feature 71A to the point feature 72, is set as the point feature 71B, which is a new reference node.

[0095] The registration unit 12 extracts point features 72 to 74 from the point feature 70 included in the branch. Fig. 12 shows a state in which the registration unit 12 sets a point feature 71B for the extracted branch and extracts point features 72 to 74. The registration unit 12 deletes the extracted point feature 74 from the map 44 by setting it as a feature to be thinned out.

[0096] Fig. 13 is a diagram for explaining a fourth process performed by the server according to the embodiment to make a thinning decision. The registration unit 12 creates a map 45 shown in Fig. 13 from the map 44 shown in Fig. 12. Specifically, the registration unit 12 extracts, as a point feature 75, a target point feature whose distance from a line segment connecting point features 70 on both sides of the target point feature to the target point feature is shorter than a specific value (a reference value D1 described later). The process in which the registration unit 12 extracts the point feature 75 is the fourth process. Fig. 13 shows a state in which the registration unit 12 has extracted the point feature 75.

[0097] The registration unit 12 deletes the point features 75 extracted in the fourth process by setting them as features to be thinned out, and replaces the locations where the point features 75 have been deleted with a single line feature 80. The fifth process is the process in which the registration unit 12 deletes the point features 75 by setting them as features to be thinned out, and connects adjacent point features 70 on both sides with a single line feature 80.

[0098] Fig. 14 is a diagram for explaining a fifth process performed when the server according to the embodiment makes a thinning decision. Fig. 14 illustrates a case in which the target point feature is a point feature 70B, and the point features on both sides of the point feature 70B are point features 70A and 70C.

[0099] Point features 70A and 70B are connected by a line feature 80A, and point features 70B and 70C are connected by a line feature 80B. The registration unit 12 extracts point feature 70B when the distance from a line segment X1 connecting point features 70A and 70C on both sides of point feature 70B, which is a target point feature, to point feature 70B is equal to or less than a reference value D1.

[0100] The registration unit 12 deletes the extracted point feature 70B and the line features 80A, 80B connected to the point feature 70B by setting them as features to be thinned out. Furthermore, the registration unit 12 connects the point features 70A, 70C on both sides of the point feature 70B with a new line feature 80C. The line feature 80C is a linear feature that connects the point features 70A, 70C at the shortest distance. Therefore, the line feature 80C is placed at the position of the line segment X1 that connects the point features 70A, 70C. In this way, the registration unit 12 thins out the point feature 70B, and places the line feature 80C in place of the line features 80A, 80B so that the point features 70A, 70C that were not thinned out are connected to each other. This maintains the connection relationship between the point features 70A, 70C.

[0101] The registration unit 12 may extract point features 70 that are not adjacent to the target point feature as the point features 70A and 70C. In other words, the point features 70A and 70C are not limited to point features 70 adjacent to the target point feature 70B. For example, the registration unit 12 sets the point features 70A and 70C as point features that can be reached without passing through the point feature 70 that is a branch point when tracing the line feature 80 from the point feature 70B. Furthermore, the registration unit 12 may set the point feature 70B in order from any of the point features 70 included in the original map.

[0102] There may be cases where multiple point features 70 are arranged on the path from point feature 70A to point feature 70C. In this case, even when the registration unit 12 thins out all of the point features 70 arranged on the path from point feature 70A to point feature 70C, point feature 70A and point feature 70C are connected by a line feature 80C.

[0103] The registration unit 12 executes the above-mentioned first to fifth processes for each scale and for each area of ​​the original map to create a map 46 from the map 41. The map 46 here corresponds to the map 25 displayed on the client terminal 20.

[0104] The registration unit 12 creates a map 46 from the map 41, and sets some of the features included in the original map as features to be thinned based on the difference between the map 46 and the map 41. That is, the registration unit 12 creates updated thinning information 33 indicating the features to be thinned by comparing the features included in the map 46 with the features included in the map 41. In this updated thinning information 33, point features 70 included in the map 41 but not included in the map 46 are registered as point features 70 to be thinned. On the other hand, in the updated thinning information 33, point features 70 included in both the maps 41 and 46 are registered as point features 70 not to be thinned. In addition, in the updated thinning information 33, line features 80A and 80B to be deleted and line feature 80C to be added are registered.

[0105] If the registration unit 12 can display the map 25 within a specific processing load during the first process through the fourth process, the registration unit 12 ends the thinning-out determination process for the point features 70 at this point.

[0106] On the other hand, if the registration unit 12 cannot display the map 25 within the specific processing load even after executing the first process to the fifth process, it changes at least one of the reference value L and the reference value D1 described above to a larger value and executes the first process to the fifth process on the map 46. In this case as well, if the registration unit 12 can display the map 25 within the specific processing load during the first process to the fourth process, it ends the thinning determination process of the point feature 70 at this point.

[0107] That is, the registration unit 12 repeats the first to fifth processes while updating at least one of the reference value L and the reference value D1 to a larger value until the map 25 can be displayed within a specific processing load.

[0108] The server 10 creates map information 56 based on the map display request 51 received from the client terminal 20. That is, the server 10 creates map information 56 corresponding to the map 25 obtained by thinning out specific features from the original map based on the map display request 51. This map information 56 is information that enables the map 25 to be displayed as detailed as possible within a specific processing load. This enables the client terminal 20 to display the map 25 as detailed as possible within a specific processing load based on the map information 56.

[0109] 15 is a diagram for explaining map areas set when the server according to the embodiment creates update thinning information. When creating update thinning information 33 for each map area set in the original map, the registration unit 12 sets the map areas so that the map areas overlap each other.

[0110] FIG. 15 shows a case where the registration unit 12 sets map regions 61 to 64. The map regions 61 to 64 are adjacent to each other and share overlapping regions. When the registration unit 12 determines that a target point feature is to be thinned out in any of the map regions 61 to 64, the registration unit 12 determines the target point feature as a thinned out feature. In other words, the registration unit 12 determines a feature that is determined to be thinned out in at least one map region for the overlapping region as a thinned out feature. That is, the registration unit 12 creates updated thinning information 33 in which a feature that is determined to be thinned out in any of the map regions 61 to 64 is set as a thinning target. When a wide area is displayed at a small scale, the thinning rate is high, and when it is a medium scale, the thinning rate is to a certain extent. When it is a large scale such as 1 / 500, only a narrow area is displayed, and the registration unit 12 hardly needs to thin out. In order to accommodate such changes in the thinning rate according to the scale, the registration unit 12 performs a process of determining which feature to thin for each scale while changing the size of the range to be displayed.

[0111] Therefore, for the overlapping areas, the client terminal 20 causes the display unit 24 to display features that are determined not to be thinned in all of the map areas 61 to 64. In other words, for the overlapping areas, the client terminal 20 does not cause the display unit 24 to display features that are determined to be thinned in at least one map area.

[0112] Also, in the present embodiment, a case has been described in which the server 10 performs a thinning-out determination and creates the updated thinning information 33 when a change has been made to the original map, but the timing of the thinning-out determination process is not limited to this timing. That is, in the present embodiment, a case has been described in which the server 10 does not perform a thinning-out determination process when the client terminal 20 actually displays the map 25, but the server 10 may perform a thinning-out determination when a map display request 51 is received.

[0113] In addition, in the present embodiment, a case has been described in which server 10 creates map information 56 corresponding to map display request 51 when map display request 51 is received, but the timing for creating map information 56 is not limited to this timing. That is, server 10 may create map information 56 for each area and scale of map 25 when creating update thinned information 33. When server 10 creates map information 56 before map display request 51 is sent, server 10 stores the created map information 56 in thinned information DB 40.

[0114] When the client terminal 20 is displaying a map 25, if the user issues an instruction to change the display area (an instruction to scroll the screen), the client terminal 20 transmits a new map display request 51 corresponding to the scroll instruction to the server 10. As a result, the client terminal 20 receives new map information 56 corresponding to the scroll instruction from the server 10, and displays a new map 25 corresponding to the scroll instruction.

[0115] The map display system 1 may be applied to facilities other than power system facilities. The map display system 1 is also applicable to social infrastructure facilities (social infrastructure business) such as sewerage facilities and road facilities. When the map display system 1 is applied to sewerage facilities, the point features 70 are manholes, etc., and the line features 80 are pipes, etc. When the map display system 1 is applied to road facilities, the point features 70 are bridges, traffic lights, etc., and the line features 80 are roads, etc.

[0116] Next, a description will be given of the hardware configurations of the server 10 and the client terminal 20. Note that since the hardware configurations of the server 10 and the client terminal 20 are similar, the hardware configuration of the server 10 will be described here.

[0117] The server 10 is realized by a processing circuit. The processing circuit may be a processor and memory that executes a program stored in a memory, or may be dedicated hardware such as a dedicated circuit. The processing circuit is also called a control circuit.

[0118] FIG. 16 is a diagram showing an example of the configuration of a processing circuit when the processing circuit included in the server according to the embodiment is realized by a processor and a memory. The processing circuit 90 shown in FIG. 16 is a control circuit and includes a processor 91 and a memory 92. When the processing circuit 90 is configured with the processor 91 and the memory 92, each function of the processing circuit 90 is realized by software, firmware, or a combination of software and firmware. The software or firmware is described as a program and stored in the memory 92. In the processing circuit 90, each function is realized by the processor 91 reading and executing the program stored in the memory 92. That is, the processing circuit 90 includes a memory 92 for storing a program that results in the processing of the server 10 being executed. This program can also be said to be a program for causing the server 10 to execute each function realized by the processing circuit 90. This program may be provided by a storage medium in which the program is stored, or may be provided by other means such as a communication medium. The above program can also be said to be a program for causing the server 10 to execute various processes for creating and transmitting the map information 56.

[0119] Here, the processor 91 is, for example, a CPU (Central Processing Unit), a processing device, an arithmetic device, a microprocessor, a microcomputer, or a DSP (Digital Signal Processor), etc. Also, the memory 92 is, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable ROM), an EEPROM (Electrically EPROM), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disc), etc.

[0120] Fig. 17 is a diagram showing an example of a processing circuit in the case where the processing circuit of the server according to the embodiment is configured with dedicated hardware. The processing circuit 93 shown in Fig. 17 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination of these. The processing circuit 93 may be partially realized with dedicated hardware and partially realized with software or firmware. In this way, the processing circuit 93 can realize each of the above-mentioned functions by dedicated hardware, software, firmware, or a combination of these.

[0121] The communication unit 11, the registration unit 12, and the map information generation unit 13 may be realized by using separate programs. That is, the processing circuits 90 and 93 may execute the processing by the server 10 by using a communication program corresponding to the communication unit 11, a registration program corresponding to the registration unit 12, and a map information creation program corresponding to the map information generation unit 13.

[0122] In addition, in the case of the client terminal 20, the editing unit 22, the communication unit 23, and the display unit 24 may be realized by using separate programs. That is, the processing circuits 90 and 93 of the client terminal 20 may execute the processing by the client terminal 20 by using an editing program corresponding to the editing unit 22, a communication program corresponding to the communication unit 23, and a display program corresponding to the display unit 24.

[0123] Thus, according to the embodiment, the map information generating unit 13 of the server 10 creates the map information 56 so that the processing load for displaying the map 25, which is a thinned map of the original map, is equal to or less than a specific value, so that it is possible to create the map information 56 for displaying the detailed map 25 within a desired processing load. Also, the client terminal 20 is able to display the detailed map 25 within a desired processing load.

[0124] In the embodiment, the registration unit 12 of the server 10 obtains the updated feature information 32 corresponding to the feature editing information 31 from the feature DB 60, and uses the updated feature information 32 to create updated thinning information 33 in which whether or not to display a feature is set for each feature and for each scale so that the processing load is equal to or less than a specific value. Then, the map information generation unit 13 obtains feature information included in the display area from the feature DB 60 as range feature information 53 based on a map display request 51. Furthermore, the map information generation unit 13 obtains thinning information corresponding to the features included in the range feature information 53 from the thinning information DB 40 as request thinning information 55, and creates map information 56 using the range feature information 53 and the request thinning information 55. In this way, when the server 10 receives a map display request 51, it can create map information 56 in a short time using the request thinning information 55.

[0125] Furthermore, the map information generation unit 13 of the server 10 uses the request thinning information 55 to thin out the point features 70 and line features 80, and reconstructs the line features 80 at the locations where the point features 70 have been thinned out. This enables the server 10 to create map information 56 for displaying the map 25 within a desired processing load while maintaining the overview of the original map.

[0126] In addition, the map information generation unit 13 of the server 10 acquires the request thinning information 55 from the thinning information DB 40 based on the feature identification information 54 contained in the range feature information 53, thereby enabling the server 10 to easily acquire the request thinning information 55.

[0127] In addition, since the registration unit 12 of the server 10 thins out features in order of priority, the server 10 can easily keep the processing load when displaying the map 25 within a desired processing load.

[0128] Furthermore, the registration unit 12 of the server 10 derives the priority of thinning out each target point feature based on the priority derivation elements (1) to (5) described above, so that it is possible to lower the priority of thinning out for features with high importance and to raise the priority of thinning out for features with low importance when displaying the map 25. This enables the server 10 to thin out features with low importance while leaving features with high importance.

[0129] Furthermore, the registration unit 12 of the server 10 divides the display area on the map 25 into a plurality of map areas 61-64, and executes a thinning-out determination as to whether or not to thin out features for each of the map areas 61-64. This enables the server 10 to reduce the processing load when performing an update process of the overall thinning information 82.

[0130] Furthermore, the registration unit 12 of the server 10 overlaps the map areas 61 to 64, and thins out the features when it is determined that features should be thinned out in at least one of the overlapping map areas. This enables the server 10 to accurately extract features to be thinned out.

[0131] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies. Parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0132] 1 map display system, 10 server, 11, 23 communication unit, 12 registration unit, 13 map information generation unit, 20 client terminal, 21 input unit, 22 editing unit, 24 display unit, 25, 41-46 map, 31 feature editing information, 32 updated feature information, 33 updated thinning information, 40 thinning information DB, 51 map display request, 52 range feature acquisition request, 53 range feature information, 54 feature identification information, 55 request thinning information, 56 map information, 60 feature DB, 61-64 map area, 70, 70A-70C, 71A, 71B, 72-75 point feature, 80, 80A-80C line feature, 81 whole feature information, 82 whole thinning information, 85 scale information, 90, 93 processing circuit, 91 processor, 92 Memory.

Claims

1. a communication unit that receives a map display request from a terminal, the map display request specifying at least one of a display area and a scale of the infrastructure facility on the map; a map information generating unit that generates map information for displaying a thinned map in which some of the features included in the map are thinned out based on the map display request; Equipped with the map information generation unit acquires, based on the map display request, information on the features included in the display area from a first database that stores information on the features as range feature information, acquires, from a second database that stores thinning information that specifies whether each of the features is to be displayed on the thinned map, the thinning information corresponding to the features included in the range feature information as request thinning information, and creates the map information using the range feature information and the request thinning information; The communication unit transmits the map information to the terminal. A map information creation device comprising:

2. a registration unit that, when the communication unit receives feature editing information indicating editing content of the feature, obtains feature information that is information on the feature corresponding to the feature editing information from the first database, creates the thinning information set for each scale using the feature information, and registers the thinning information in the second database.

2. The map information generating device according to claim 1,

3. the features include point features that are displayed as points on the map and line features that are displayed as lines on the map; The map information generating unit thinning out the point features and the line features using the request thinning information, and reconstructing the line features so that the connection relationships between the point features that were not thinned out are maintained; 3. The map information generating device according to claim 2.

4. The information on the features and the thinning information include identification information for identifying the features, The map information generating unit acquiring the request thinning information from the second database based on the identification information included in the range feature information; 4. The map information generating device according to claim 2 or 3.

5. A thinning priority is set for the feature, The registration unit thins out the features in order of priority.

5. The map information generating device according to claim 2, wherein the map information generating device is a map information generating device.

6. The infrastructure facility is a power system facility, The point features include at least one of a utility pole, a transformer, and a switchgear; The line feature includes an electric wire.

4. The map information generating device according to claim 3.

7. The registration unit is deriving the priority of thinning based on attributes set for the point feature, whether the point feature is a branching point on the map, whether the point feature is an end point, the distance from a point feature that is a branching point of the line feature on the map, or the distance from a line segment connecting the point features on both sides of the point feature to the point feature sandwiched between the point features on both sides; 4. The map information generating device according to claim 3.

8. The registration unit divides the display area into a plurality of map areas, and executes a thinning-out determination as to whether or not to thin out the features for each of the map areas.

3. The map information generating device according to claim 2.

9. the registration unit overlaps the map regions, and thins out the features when it is determined that the features should be thinned out in at least one of the map regions for the overlapping regions; 9. The map information generating device according to claim 8.

10. a terminal that transmits a map display request specifying at least one of a display area and a scale of an infrastructure facility on a map; a map information creation device that receives the map display request, creates map information for displaying a thinned map in which some of the features included in the map are thinned based on the map display request, and transmits the map information to the terminal; Equipped with the map information creation device acquires, based on the map display request, information on the features included in the display area from a first database that stores information on the features as range feature information, acquires, from a second database that stores thinning information that specifies whether or not each of the features is to be displayed on the thinned map, the thinning information corresponding to the features included in the range feature information as request thinning information, and creates the map information using the range feature information and the request thinning information; The terminal displays the thinned map based on the map information. A map display system comprising:

11. a map information generating step of generating map information for displaying a thinned map in which some of the features included in the map are thinned out based on a map display request received from the terminal, the map display request specifying at least one of a display area and a scale of the infrastructure facility on the map; In the map information generating step, information on the features included in the display area is obtained as range feature information from a first database that stores information on the features based on the map display request, and thinning information corresponding to features included in the range feature information among the features is obtained as request thinning information from a second database that stores thinning information that specifies whether each of the features is to be displayed on the thinned map, and the map information is created using the range feature information and the request thinning information. A map information creation program comprising:

Images