An Automatic Extraction Method and System for Complex Road Network Topological Relationships in the Case of Multiple Breakpoints

Abstract

The present invention discloses a method and system for automatically extracting complex road network topological relationships in the case of multiple breakpoints, which relates to the technical field of road network data processing, and solves the technical problem that in the prior art, the spatial connection relationship of road segments cannot be effectively utilized in the case of multiple breakpoints, resulting in inconvenience in extracting the road network topological structure. The present invention includes splitting the road segments of the road network data, traversing the split road segments to determine the breakpoints and record the target adjustment straight line numbers corresponding to the breakpoints, then converting the road network data into an undirected graph according to the breakpoints and the corresponding target adjustment straight lines, dividing the undirected graph into connected subgraphs, selecting the base straight lines in the connected subgraphs and projecting the nodes of other straight lines onto the base straight lines, adjusting the coordinates of the nodes according to the projection positions of all the projected nodes on the base straight lines to obtain the adjusted road network data, and regenerating the topological relationship according to the adjusted road network data. The present invention reduces the threshold for extracting the road network topological relationship and greatly saves the labor cost.

Description

Technical Field

[0001] The present invention relates to the technical field of road network data processing, and particularly to an automatic extraction method and system for complex road network topological relationships in the case of multiple breakpoints. Background Art

[0002] As basic information data for the construction of smart cities, road network topological information plays an important supporting role in traffic flow analysis, vehicle path navigation, and resource scheduling optimization. However, the existing extraction of road network topological information is usually carried out on the premise of high-quality map data, using the spatial connection relationship of road segments for extraction. Moreover, in actual situations, the quality of the obtained data varies, and it is difficult to guarantee the spatial connection relationship of the road network. Especially in the case of multiple breakpoints, it is unrealistic to extract the road network topological structure using the spatial connection relationship of road segments. In addition, for large-scale and complex road networks, the cost of manually processing breakpoints is too high. Summary of the Invention

[0003] In order to solve the problems existing in the above-mentioned prior art, the present invention provides an automatic extraction method and system for complex road network topological relationships in the case of multiple breakpoints, and solves the technical problem that in the case of multiple breakpoints in the prior art, the spatial connection relationship of road segments cannot be effectively utilized, resulting in inconvenience in extracting the road network topological structure.

[0004] An automatic extraction method for complex road network topological relationships in the case of multiple breakpoints includes:

[0005] Splitting the road segments of the road network data, traversing the split road segments, determining the breakpoints and recording the target adjustment lines corresponding to the road breakpoints, then converting the road network data into an undirected graph according to the breakpoints and the corresponding target adjustment lines, further dividing the undirected graph into connected subgraphs, selecting the base lines in the connected subgraphs and projecting the nodes of other lines onto the base lines, adjusting the coordinates of the nodes according to the projection positions of all the projected nodes on the base lines to obtain the adjusted road network data, and regenerating the topological relationship according to the adjusted road network data.

[0006] Further, the traversing the split road segments to determine the breakpoints and the target adjustment lines corresponding to the breakpoints includes:

[0007] Judging whether the coordinate points of the current line need to be adjusted by accessing whether there are other lines with the same direction within the specified range of each coordinate point of a certain line; if there are other lines with the same direction within the specified range of the coordinate points of the currently accessed line, select the one with the closest distance and record its number as the target adjustment line of the breakpoint, and continue to access until all the coordinate points of all road segments have been accessed. The specified range is within 1m.

[0008] Further, the adjusting the node coordinates of all lines according to the projection positions includes:

[0009] If the node projection position is in the area outside the starting point of the base line, modify the node coordinates to the starting point coordinates of the base line; if the node projection position is in the area outside the ending point of the base line, modify the node coordinates to the ending point coordinates of the base line; if the node projection position is in the area corresponding to the base line, further determine the distances between the node projection position and the starting point and the ending point of the base line respectively, and modify the node coordinates to the coordinates closer to either of them.

[0010] Furthermore, the regenerating the topological relationship according to the adjusted road network data includes: removing duplicates from the longitude and latitude coordinates of the starting and ending points of all road segments in the road network to obtain the number of different coordinates, which is the maximum node number; then numbering the starting and ending points of all road segments, and each longitude and latitude coordinate is uniquely numbered; based on the node numbers, obtain the connected node numbers of the road segments according to the longitude and latitude coordinates of the starting and ending points of the road segments to realize the construction of the road network topology.

[0011] Furthermore, the split road segment only includes the starting point and the ending point.

[0012] Furthermore, the base line is the straight line with the maximum length in the connected subgraph.

[0013] Furthermore, the nodes in the undirected graph are road segments, and the edges of the undirected graph indicate that there is a break point in one of the two road segments and it can be adjusted to the other road segment.

[0014] Furthermore, the connected subgraph indicates that the road segments within the subgraph can be merged into one road segment.

[0015] A complex road network topology relationship automatic extraction system in the case of multiple break points, used to implement a complex road network topology relationship automatic extraction method in the case of multiple break points, including: a target adjustment straight line confirmation module, a straight line merging module, a coordinate adjustment module, and a road network topology extraction module;

[0016] The target adjustment straight line confirmation module is used to split the road segments of the road network data, traverse the split road segments, determine the break points and record the target adjustment straight lines corresponding to the break points;

[0017] The straight line merging module is used to convert the road network data into an undirected graph according to the break points and the corresponding target adjustment straight lines, then divide the undirected graph into connected subgraphs, select the base line in the connected subgraph and project the nodes of other straight lines onto the base line;

[0018] The coordinate adjustment module is used to adjust the coordinates of the nodes according to the projection positions of all the projected nodes on the base line to obtain the adjusted road network data;

[0019] The road network topology extraction module is used to regenerate the topological relationship according to the adjusted road network data.

[0020] The beneficial effects of the present invention include: for road network data with multiple breakpoints, first judge the breakpoints and the corresponding target adjustment lines, then integrate the target adjustment lines by projection, adjust the coordinates of the line nodes according to the projection positions of the line nodes, and finally regenerate the topological relationship according to the adjusted line node coordinates, so that the topological relationship of a large-scale road network can be extracted under the condition of low-quality road network data, reducing the threshold for extracting the topological relationship of the road network and greatly saving labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a flowchart of an automatic extraction method for the topological relationship of a complex road network in the case of multiple breakpoints according to an embodiment of the present application.

[0022] Figure 2 It is a display of the LineString data format of a line according to an embodiment of the present application.

[0023] Figure 3 It is a possible breakpoint type according to an embodiment of the present application.

[0024] Figure 4 It is a possible breakpoint type according to an embodiment of the present application.

[0025] Figure 5 It is the projection area division according to an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Apparently, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Therefore, the detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application to be protected, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0027] An automatic extraction method for the topological relationship of a complex road network in the case of multiple breakpoints, as Figure 1 shown, includes:

[0028] Obtain the original road network vector data, i.e., the road network data. Split the segments of the road network data, that is, split all the LineString segments in the road network. Traverse the split segments, determine the breakpoints and record the target adjustment lines corresponding to the breakpoints. Then, convert the road network data into an undirected graph based on the breakpoints and the corresponding target adjustment lines. Next, divide the undirected graph into connected subgraphs. Select the base lines in the connected subgraphs and project the nodes of other lines onto the base lines. Adjust the coordinates of the nodes according to the projection positions of all the projected nodes on the base lines to obtain the adjusted road network data, and regenerate the topological relationship based on the adjusted road network data.

[0029] In this embodiment, each segment in the original road network is represented in the LineString data format. In the LineString data format, a line is composed of several coordinate points, and these coordinate points are connected in sequence to form a road, as Figure 2 shown. Split all segments consisting of three or more coordinate points into segments that only contain two coordinate points (i.e., the starting point and the ending point). At the same time, uniquely number all the coordinate points according to longitude and latitude, and record the segment numbers corresponding to each coordinate point to ensure that the connection relationship between segments in the original road network will not be affected in subsequent operations.

[0030] In actual road vector data, there are various possible situations for breakpoints, Figure 3 、 4 showing the common breakpoint types in the data.

[0031] In another embodiment, the traversing the split segments to determine the breakpoints and the target adjustment lines corresponding to the breakpoints includes:

[0032] Judge whether the coordinate points of the current line need to be adjusted by accessing whether there are other lines with the same direction within the specified range of each coordinate point of a certain line; if there are other lines with the same direction within the specified range of the coordinate points of the currently accessed line, select the closest one and record its number as the target adjustment line for this breakpoint, and continue to access until all coordinate points of all segments have been accessed.

[0033] In this embodiment, the specified range refers to within 1m. Specifically: Judge whether the coordinate points of the current line A are breakpoints by accessing whether there are other lines with the same direction within 1m around each coordinate point of the current line A (excluding the line with a distance of 0).

[0034] If there are other lines with the same direction within 1m around the coordinate point a of the current line A, select the closest line B and record its number as the target adjustment line for this breakpoint.

[0035] For example, in Figure 3In the breakpoint type 1, there is a straight line 2 within 1m around the c coordinate point of the straight line 1, and the directions of the straight line 1 and the straight line 2 are the same. Therefore, the straight line 2 is the target adjustment straight line of the c coordinate point of the straight line 1.

[0036] In another embodiment, the adjustment of the node coordinates of all straight lines according to the projection position includes:

[0037] If the node projection position is in the area outside the starting point of the base straight line, the node coordinates are modified to the starting point coordinates of the base straight line; if the node projection position is in the area outside the ending point of the base straight line, the node coordinates are modified to the ending point coordinates of the base straight line; if the node projection position is in the area corresponding to the base straight line, further judge the distances between the node projection position and the starting point and the ending point of the base straight line respectively, and modify the node coordinates to the coordinates with a closer distance between the two. After the adjustment of the node coordinates, update the starting and ending point coordinates of all road segments with this node as the starting or ending point.

[0038] In this embodiment, as Figure 5 shown, the projection positions on the base straight line are divided into the area head beyond outside the starting point of the base straight line, the area tai l beyond outside the ending point of the base straight line, and the area with in corresponding to the base straight line.

[0039] In another embodiment, the regeneration of the topological relationship according to the adjusted road network data includes: removing duplicates from the longitude and latitude coordinates of the starting and ending points of all road segments in the road network to obtain the number of different coordinates, which is the maximum node number; then number the starting and ending points of all road segments, and each longitude and latitude coordinate is uniquely numbered; based on the node numbers, obtain the connected node numbers of the road segments according to the longitude and latitude coordinates of the starting and ending points of the road segments to realize the construction of the road network topology.

[0040] In another embodiment, the split road segment only includes the starting point and the ending point.

[0041] In another embodiment, the base straight line is the straight line with the maximum length in the connected subgraph.

[0042] In another embodiment, the nodes in the undirected graph are road segments, and the edges of the undirected graph indicate that there is a breakpoint in one of the two road segments and it can be adjusted to the other road segment.

[0043] In another embodiment, the connected subgraph means that the road segments within the subgraph can be merged into one road segment.

[0044] In another embodiment, there is also a complex road network topology relationship automatic extraction system in the case of multiple breakpoints, which is used to implement a complex road network topology relationship automatic extraction method in the case of multiple breakpoints, including: a target adjustment straight line confirmation module, a straight line merging module, a coordinate adjustment module, and a road network topology extraction module;

[0045] The target adjustment line confirmation module is used to split the road section of the road network data, traverse the split road sections, determine the break points and record the target adjustment lines corresponding to the break points;

[0046] The line merging module is used to convert the road network data into an undirected graph according to the break points and the corresponding target adjustment lines, then divide the undirected graph into connected subgraphs, select the base lines in the connected subgraphs, and project the nodes of other lines onto the base lines;

[0047] The coordinate adjustment module is used to adjust the coordinates of the nodes according to the projection positions of all the projected nodes on the base lines to obtain the adjusted road network data;

[0048] The road network topology extraction module is used to regenerate the topological relationship according to the adjusted road network data.

[0049] Specifically, in this embodiment, a data acquisition module is further included, which is used to acquire the original road network vector data.

[0050] The above embodiments only represent the specific implementation manners of the present application, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the protection scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the technical solution of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application.

Claims

1. An automatic extraction method for complex road network topological relationships in the case of multiple breakpoints, characterized in that Including: Split the road segments in the road network data, traverse the split road segments, determine the breakpoints and record the target adjustment lines corresponding to the breakpoints, then convert the road network data into an undirected graph according to the breakpoints and the corresponding target adjustment lines, and then divide the undirected graph into connected subgraphs. Select the base line in the connected subgraph and project the nodes of other lines onto the base line, and adjust the coordinates of the nodes according to the projection positions of all the projected nodes on the base line to obtain the adjusted road network data, and regenerate the topological relationship according to the adjusted road network data.

2. The automatic extraction method for complex road network topological relationships in the case of multiple breakpoints according to claim 1, characterized in that, The traversing the split road segments to determine the breakpoints and the target adjustment lines corresponding to the breakpoints includes: Judge whether the coordinate points of the current line need to be adjusted by accessing whether there are other lines with the same direction within the specified range of each coordinate point of a certain line; if there are other lines with the same direction within the specified range of the coordinate points of the currently accessed line, select the line with the closest distance and record its number as the target adjustment line of the breakpoint, and continue to access until all coordinate points of all road segments have been accessed.

3. A method for automatically extracting complex road network topological relationships in the case of multiple breakpoints, as claimed in claim 1, characterized in that The adjusting the node coordinates of all lines according to the projection position includes: If the node projection position is in the area outside the starting point of the base line, modify the node coordinates to the starting point coordinates of the base line; if the node projection position is in the area outside the ending point of the base line, modify the node coordinates to the ending point coordinates of the base line; if the node projection position is in the area corresponding to the base line, further judge the distances between the node projection position and the starting point and the ending point of the base line respectively, and modify the node coordinates to the coordinates with the closer distance between the two.

4. The automatic extraction method for complex road network topological relationships in the case of multiple breakpoints according to claim 1, characterized in that, The regenerating the topological relationship according to the adjusted road network data includes: removing duplicates from the longitude and latitude coordinates of the starting and ending points of all road segments in the road network to obtain the number of different coordinates, which is the maximum node number; then number the starting and ending points of all road segments, and each longitude and latitude coordinate is uniquely numbered; on the basis of the node numbers, obtain the connected node numbers of the road segments according to the longitude and latitude coordinates of the starting and ending points of the road segments to realize the construction of the road network topology.

5. The automatic extraction method for complex road network topological relationships in the case of multiple breakpoints according to claim 1, characterized in that, The split road segments only include the starting point and the ending point.

6. A method for automatically extracting complex road network topological relationships in the case of multiple breakpoints, as described in claim 1, wherein The base line is the line with the maximum length in the connected subgraph.

7. A method for automatically extracting complex road network topological relationships in the case of multiple breakpoints, according to claim 1, characterized in that The nodes in the undirected graph are road segments, and the edges of the undirected graph indicate that there is a breakpoint in one of the two road segments and it can be adjusted to the other road segment.

8. A method for automatically extracting complex road network topological relationships in the case of multiple breakpoints, according to claim 1, characterized in that The connected subgraph means that the road segments within the subgraph can be merged into one road segment.

9. An automatic extraction system for complex road network topological relationships in the case of multiple breakpoints, characterized in that, A method for automatically extracting the topological relationship of a complex road network in the case of multiple breakpoints for implementing any one of claims 1-8, including: a target adjustment line confirmation module, a line merging module, a coordinate adjustment module, and a road network topology extraction module; The target adjustment line confirmation module is used to split the road segments in the road network data, traverse the split road segments, determine the breakpoints and record the target adjustment lines corresponding to the breakpoints; The line merging module is used to convert the road network data into an undirected graph according to the breakpoints and the corresponding target adjustment lines, then divide the undirected graph into connected subgraphs, select the base line in the connected subgraph and project the nodes of other lines onto the base line; The coordinate adjustment module is used to adjust the coordinates of the nodes according to the projection positions of all the projection nodes on the base line to obtain the adjusted road network data; The road network topology extraction module is used to regenerate the topological relationship according to the adjusted road network data.

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