A method for expressing intersections based on road network data and vector calculation

Abstract

The present invention discloses an intersection expression method based on road network data and vector calculation, the steps are as follows: reading road network data; extracting intersection topological connection data; sorting intersection topological edges; calculating intersection points; smoothing intersection points to make them more consistent with the actual intersection contour range; calculating intersection points of topological edges; and connecting topological edge intersection coordinates in order according to the topological point sequence of road section topological connection data to form a complete road network. The present invention has a high value of popularization and application. In the context of macro-micro integration, it can provide a reference method for intersection expression or road network visualization in micro-dimension for macro traffic simulation software such as TransCAD and TranStar.

Description

Technical Field

[0001] The invention belongs to the technical field of urban virtual simulation, and particularly relates to an intersection expression method. Background Art

[0002] Urban virtual traffic simulation technology is an important decision-making basis for urban road management and traffic control. Traditional virtual traffic simulation technology is mainly divided into two categories, one is macro traffic simulation, representative products include TransCAD, TranStar, etc., the other is micro traffic simulation, representative products include VISSIM, SUMO, TESS NG, etc. For a long time, the two types of simulation technologies have been in a state of separation. Macro traffic simulation technology mainly focuses on the overall planning of the city, with the overall flow of vehicles or vehicle groups as the research object, while micro traffic simulation technology focuses on individual vehicle behavior, and describes in detail the driving behavior of each vehicle at every moment in the traffic system and its interaction relationship. In recent years, with the development of emerging technologies such as big data, the Internet of Things, cloud computing, and artificial intelligence, as well as the requirements for the accuracy of simulation technology, macro-micro integrated traffic simulation has gradually become a hot research topic. Macro-micro integration focuses on the interaction and influence of macro traffic simulation and micro traffic simulation. The macro level is based on the traffic demand between regions, and the micro level explores the traffic behavior of each individual. The two interact with each other to strive to simulate the most realistic real traffic state.

[0003] Intersection expression technology has broad prospects and high promotion and application value in the context of macro-micro integration. The simulation calculation kernel is the key to virtual traffic simulation technology, but intersection expression technology is also crucial. Intersection expression technology is the cornerstone of the complete presentation of the road network and an important carrier for the iteration of simulation objects and the presentation of simulation results. It can more intuitively and realistically reflect the results and status of traffic simulation, especially the judgment and investigation of the traffic operation status or abnormal situation of a certain section or node during the simulation process. Existing macro-micro traffic simulation products such as TranStar and TESS NG have begun to conduct research on macro-micro integration, and have road network visualization modules in their own dimensions. However, at present, such products lack the road network visualization conversion function in the dimension of macro-micro integration, especially the intersection expression method of macro traffic simulation software in the micro dimension. Summary of the invention

[0004] In order to solve the technical problems mentioned in the above background technology, the present invention proposes an intersection expression method based on road network data and vector calculation.

[0005] In order to achieve the above technical objectives, the technical solution of the present invention is:

[0006] A method for expressing intersections based on road network data and vector calculation comprises the following steps:

[0007] (1) Reading road network data: including topological point coordinate data, road section topological connection data, and road section geometric element data;

[0008] (2) Extracting intersection topological connection data: According to the road section topological connection data read in step (1), the adjacent intersection number and the topological connection number of each intersection point are extracted in turn, and the intersections are classified according to the intersection as the starting point or the arrival point. At the same time, it is determined whether each topological edge has a subtending edge, that is, a topological edge in the opposite direction from the starting point to the end point of the road section;

[0009] (3) Sort the topological edges of the intersection;

[0010] (4) Calculate intersection points;

[0011] (5) Smoothing the intersection points solved in step (4) to make them more consistent with the actual intersection contour range;

[0012] (6) Calculate the intersection points of topological edges;

[0013] (7) According to the topological point sequence of the road section topological connection data, the topological edge intersection coordinates solved in step (6) are sequentially connected to form a complete road network.

[0014] Furthermore, in step (1), the topological point coordinate data includes the topological point number, the topological point x coordinate, and the topological point y coordinate; the road section topological connection data includes the road section starting node number, the road section ending node number, the topological connection number, the number of topological points, and the topological point number sequence; the road section geometric element data includes the road section starting point, the road section end point, the number of motor vehicle lanes, the motor vehicle lane width, the non-motor vehicle lane width, and the separation method between the motor vehicle lane and the non-motor vehicle lane.

[0015] Furthermore, in the topological point coordinate data, the topological point x coordinate and the topological point y coordinate are both represented by the same reference coordinate system.

[0016] Furthermore, in the road section topological connection data, different driving directions are distinguished separately, that is, a two-way road is composed of two topological connection edges, and the two are opposite edges to each other.

[0017] Furthermore, the specific process of step (3) is as follows:

[0018] (31) Calculate the angle of the topological segment of the intersection: select the first and last topological segments of each topological edge of the intersection, where the first topological segment is selected for the topological edge with the intersection as the starting point, and the last topological segment is selected for the topological edge with the intersection as the arrival point; calculate the angle between each topological segment and the counterclockwise direction of the positive semi-axis of the x-axis based on the Cartesian coordinate system;

[0019] (32) Topological edge angle sorting: sort the topological edges of each intersection. The sorting rule is from small to large according to the angle of the corresponding topological segment. For topological segments with the same angle, the topological edges with the intersection as the starting point are sorted before the topological edges with the intersection as the arrival point.

[0020] Furthermore, the specific process of step (4) is as follows:

[0021] (41) Road width calculation: Calculate the road width of each topological edge of each intersection based on the road segment geometric element data read in step (1). The calculation formula is: road width = number of motor vehicle lanes * width of motor vehicle lane + width of non-motor vehicle lane + width occupied by the separation method between motor vehicle lanes and non-motor vehicle lanes;

[0022] (42) According to the topological edge sorting of the intersection, the corresponding first and last topological segments are selected in combination with the topological edge classification and expressed in the form of a vector; according to whether there is an opposite edge, the topological segment vector is translated perpendicular to the vector direction. If there is an opposite edge, the topological segment vector is translated to the right by a distance corresponding to the width of the road. If there is no opposite edge, the topological segment vector is translated to the left and right by a distance corresponding to half the width of the road. According to the topological edge sorting of the intersection, the two vectors are intersected and the intersection point is solved.

[0023] Furthermore, in step (41), the width occupied by the separation between the motor vehicle lane and the non-motor vehicle lane adopts the default value: 1 meter when there is a separation zone, and 0 meter when there is no separation zone.

[0024] Furthermore, in step (4), when the angle difference between two adjacent topological segments at the intersection is close to or equal to 180°, the intersection position of the parallel lines of the topological segments is far from the intersection or does not exist. For such cases, the coordinates of the intersection are determined based on the parallel lines of the topological segments that are closer to the intersection point.

[0025] Furthermore, in step (5), Bezier curve fitting is used for smoothing.

[0026] Furthermore, in step (6), each topological edge is composed of a number of ordered topological segments, and the parallel vectors of two topological segments intersect in sequence. The selection of parallel vectors is determined according to the type of the topological edge.

[0027] The beneficial effects brought by adopting the above technical solution are:

[0028] First, the present invention provides a reference for the visual expression of the macroscopic road network structure in the microscopic dimension under the background of macro-micro integration, filling the gap in this type of problem; secondly, the present invention uses vector calculation as a solution to reasonably determine the intersection range and road range, which is universal and suitable for the intersection visualization display of major macroscopic traffic simulation software. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a flow chart of the method of the present invention;

[0030] Figure 2 Schematic diagram of the road network structure in the embodiment;

[0031] Figure 3 Schematic diagram of intersection point calculation in the embodiment;

[0032] Figure 4 This is a schematic diagram of special intersection processing in the embodiment;

[0033] Figure 5 This is a diagram showing the effect of intersection smoothing in the embodiment;

[0034] Figure 6 Schematic diagram of the topological edge connection process in the embodiment;

[0035] Figure 7 This is a complete road network result diagram in the microscopic dimension in the embodiment. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

[0037] This example uses the basic road network in the central urban area of ​​Phnom Penh, the capital of Cambodia, as the research object, and realizes its intersection expression in the microscopic dimension according to the data processing steps in the technical solution. Figure 1 , including the following 7 steps:

[0038] (1) Data reading: This example takes the basic road network in the central urban area of ​​Phnom Penh, the capital of Cambodia, as the research object. The road network structure is as follows: Figure 2 As shown. Read the macro-road network topological connection relationship and geometric element data in the example, including topological point coordinate data, section topological connection data and section geometric element data. The topological point coordinate data includes three fields: topological point number, topological point x coordinate, and topological point y coordinate. The section topological connection data includes five fields: section starting point, section end point, topological connection number, number of topological points, and topological point number sequence. The section geometric element data includes six fields: section starting point, section end point, number of motor vehicle lanes, motor vehicle lane width, non-motor vehicle lane width, and motor vehicle and non-motor vehicle separation method. The obtained topological point coordinate data table, section topological connection data table, and section geometric element data table are shown in Table 1, Table 2, and Table 3, respectively.

[0039] Table 1. Topological point coordinate data table

[0040] Topological point number Topological point x coordinate Topological point y coordinate 1 492208.453388999972958 1277470.270978000015020 2 492229.191764999995939 1277470.674929999979213 3 492323.779395000019576 1277473.117318999953568 4 492334.508386000001337 1277473.291600000113249 … … … 20540 489789.442955999984406 1275945.018731999909505

[0041] Table 2. Road segment topology connection data table

[0042]

[0043] Table 3. Road segment geometry data table

[0044]

[0045] (2) Extracting intersection topological connection data: Extract the adjacent intersection numbers of each intersection and store the topological connection data in the data format of (A, B), where A represents the starting point of the road section and B represents the end point of the road section. The intersection topological connection data table is generated as shown in Table 4.

[0046] Table 4. Intersection topology connection data table

[0047] Intersection Number Topological connection segment 1 (1,9),(1,1328),(67,1),(4171,1) 9 (9,20),(9,1318),(9,941),(1,9),(941,9),(1318,9) 1328 (1328,21),(1,1328),(1318,1328) 20 (20,50),(20,1336),(9,20),(34,20) … … 4716 (4716,2336),(4716,2338),(4715,4716),(5834,4716)

[0048] (3) Intersection topological edge sorting: Calculate the angle between the first and last topological segments of the topological edge obtained in step (2) and the positive semi-axis of the x-axis. The topological edge of the "starting from the intersection" type selects the first topological segment for calculation, and the topological edge of the "reaching the intersection" type selects the last topological segment for calculation. Taking intersection number 1 as an example, the topological edges (1,9) and (1,1328) select the first topological segment. By querying Table 2, we can obtain the topological segments (1,2) and (1,4188) respectively. The topological edges (67,1) and (4171,1) select the last topological segment. By querying Table 2, we can obtain the topological segments (718,1) and (4069,1) respectively. The angle between the topological segment and the positive semi-axis of the x-axis is calculated by the coordinates of each topological point, and sorted in ascending order. For topological edges with the same angle, the "starting from the intersection" type is ranked first and the "reaching the intersection" type is ranked last, so as to facilitate the subsequent calculation of the topological segment intersection. The final intersection topological edge sorting table is shown in Table 5.

[0049] Table 5. Intersection topology edge sorting table

[0050] Intersection Number Topological connection segment 1 (1,9),(1,1328),(4171,1),(67,1) 9 (9,20),(9,1318),(1318,9),(1,9),(9,941),(941,9) 1328 (1318,1328),(1328,21),(1,1328) 20 (34,20),(9,20),(20,1336),(20,50) … … 4716 (4716,2338),(4716,2336),(5834,4716),(4715,4716)

[0051] (4) Intersection point calculation: According to the intersection topology edge sorting table, the corresponding first and last topology segments are selected in combination with the topology edge classification and expressed in vector form. The vector is translated according to whether there is an opposite edge perpendicular to the vector direction. If there is an opposite edge, the topology segment vector is translated to the right by a distance corresponding to the width of the road. If there is no opposite edge, the topology segment vector is translated to the left and right by a distance corresponding to half the width of the road. According to the intersection topology edge sorting table, the two vectors intersect and the intersection point is solved. The schematic diagram of intersection point calculation is shown in Figure 3 The coordinates of the intersection points arranged in order are shown in Table 6.

[0052] Table 6. Intersection point sequence

[0053]

[0054] (5) Special intersection processing: During the calculation process of step (4), when the angle difference between two adjacent topological segments at the intersection is close to or equal to 180°, the intersection point of the parallel lines of the topological segments may be far away from the intersection or may not exist. In this case, the coordinates of the intersection point are determined based on the parallel lines of the topological segments that are closer to the intersection point, such as Figure 4 shown.

[0055] (6) Intersection smoothing: Based on the vector intersection coordinates obtained in steps (4) and (5), Bezier curve fitting is used for smoothing to better fit the intersection contour. Figure 5 shown.

[0056] (7) Topological edge intersection calculation: The principle is the same as step (4), and the topological edge intersection calculation is performed. Each topological edge is composed of several ordered topological segments. The parallel vectors of two topological segments intersect in sequence. The parallel vector selection is determined according to the topological edge category. Finally, the topological edge intersection sequence is obtained as shown in Table 7.

[0057] Table 7. Topological edge intersection sequence

[0058]

[0059] (8) Topological edge connection: The topological point sequence in the road segment topological connection data table is sequentially connected to the vector intersection coordinates solved in step (6). The topological edge connection process is as follows: Figure 6 The final complete road network result is shown in Figure 7 shown.

[0060] The embodiments are only for illustrating the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for expressing intersections based on road network data and vector calculation, characterized in that: The following steps are involved: (1) Reading road network data: including topological point coordinate data, road section topological connection data, and road section geometric element data; (2) Extracting intersection topological connection data: According to the road section topological connection data read in step (1), the adjacent intersection number and the topological connection number of each intersection point are extracted in turn, and the intersections are classified according to the intersection as the starting point or the arrival point. At the same time, it is determined whether each topological edge has a subtending edge, that is, a topological edge in the opposite direction from the starting point to the end point of the road section; (3) Sort the topological edges of the intersection; (4) Calculate intersection points; (5) Smoothing the intersection points solved in step (4) to make them more consistent with the actual intersection contour range; (6) Calculate the intersection points of topological edges; (7) According to the topological point sequence of the road section topological connection data, the topological edge intersection coordinates solved in step (6) are sequentially connected to form a complete road network.

2. The intersection expression method based on road network data and vector calculation according to claim 1 is characterized in that: In step (1), the topological point coordinate data includes the topological point number, the topological point x coordinate, and the topological point y coordinate; the road section topological connection data includes the road section starting node number, the road section ending node number, the topological connection number, the number of topological points, and the topological point number sequence; the road section geometric element data includes the road section starting point, the road section end point, the number of motor vehicle lanes, the motor vehicle lane width, the non-motor vehicle lane width, and the separation method between the motor vehicle lane and the non-motor vehicle lane.

3. The intersection expression method based on road network data and vector calculation according to claim 2 is characterized in that: In the topological point coordinate data, the topological point x coordinate and the topological point y coordinate are both represented by the same reference coordinate system.

4. The intersection expression method based on road network data and vector calculation according to claim 2 is characterized in that: In the road segment topological connection data, different driving directions are distinguished separately, that is, a two-way road is composed of two topological connection edges, which are opposite edges to each other.

5. The intersection expression method based on road network data and vector calculation according to claim 1 is characterized in that: The specific process of step (3) is as follows: (31) Calculate the angle of the topological segment of the intersection: select the first and last topological segments of each topological edge of the intersection, where the first topological segment is selected for the topological edge with the intersection as the starting point, and the last topological segment is selected for the topological edge with the intersection as the arrival point; calculate the angle between each topological segment and the counterclockwise direction of the positive semi-axis of the x-axis based on the Cartesian coordinate system; (32) Topological edge angle sorting: sort the topological edges of each intersection. The sorting rule is from small to large according to the angle of the corresponding topological segment. For topological segments with the same angle, the topological edges with the intersection as the starting point are sorted before the topological edges with the intersection as the arrival point.

6. The intersection expression method based on road network data and vector calculation according to claim 1 is characterized in that: The specific process of step (4) is as follows: (41) Road width calculation: Calculate the road width of each topological edge of each intersection based on the road segment geometric element data read in step (1). The calculation formula is: road width = number of motor vehicle lanes * width of motor vehicle lane + width of non-motor vehicle lane + width occupied by the separation method between motor vehicle lanes and non-motor vehicle lanes; (42) According to the topological edge sorting of the intersection, the corresponding first and last topological segments are selected in combination with the topological edge classification and expressed in the form of a vector; according to whether there is an opposite edge, the topological segment vector is translated perpendicular to the vector direction. If there is an opposite edge, the topological segment vector is translated to the right by a distance corresponding to the width of the road. If there is no opposite edge, the topological segment vector is translated to the left and right by a distance corresponding to half the width of the road. According to the topological edge sorting of the intersection, the two vectors are intersected and the intersection point is solved.

7. The intersection expression method based on road network data and vector calculation according to claim 6 is characterized in that: In step (41), the width of the separation between the motor vehicle lane and the non-motor vehicle lane adopts the default value: 1 meter if there is a separation strip, and 0 meter if there is no separation strip.

8. The intersection expression method based on road network data and vector calculation according to claim 1 is characterized in that: In step (4), when the angle difference between two adjacent topological segments at the intersection is close to or equal to 180°, the intersection position of the parallel lines of the topological segments is far from the intersection or does not exist. For such cases, the coordinates of the intersection are determined based on the parallel lines of the topological segments that are closer to the intersection point.

9. The intersection expression method based on road network data and vector calculation according to claim 1, characterized in that: In step (5), Bezier curve fitting is used for smoothing.

10. The intersection expression method based on road network data and vector calculation according to claim 1, characterized in that: In step (6), each topological edge is composed of several ordered topological segments, and the parallel vectors of two topological segments intersect in sequence. The selection of parallel vectors is determined according to the type of topological edge.

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