Method and system for automatically extracting topological relation of complex road network under multi-breakpoint condition

Abstract

The invention discloses a method and a system for automatically extracting a complex road network topological relation under a multi-breakpoint condition, relates to the technical field of road network data processing, and solves the technical problem that a road network topological structure is inconvenient to extract due to the fact that a road section space connection relation cannot be effectively utilized under the multi-breakpoint condition in the prior art. The method comprises the steps that road sections of road network data are split, the split road sections are traversed, breakpoints are determined, target adjustment straight line numbers corresponding to the breakpoints are recorded, then the road network data are converted into an undirected graph according to the breakpoints and the corresponding target adjustment straight lines, the undirected graph is divided into connected sub-graphs, and the connected sub-graphs are connected with the road network data. A base straight line is selected from the connected subgraph, nodes of other straight lines are projected to the base straight line, coordinates of the nodes are adjusted according to projection positions of all projection nodes on the base straight line to obtain adjusted road network data, and a topological relation is regenerated according to the adjusted road network data; according to the method, the threshold of road network topological relation extraction is reduced, and the labor cost is greatly saved.

Description

Technical Field

[0001] The present invention relates to the technical field of road network data processing, and in particular to a method and system for automatically extracting topological relations of a complex road network under multi-breakpoint conditions. Background Art

[0002] As the basic information data for smart city construction, road network topology information plays an important supporting role in traffic flow analysis, vehicle path navigation, and resource scheduling optimization. However, the existing road network topology information extraction is usually carried out on the premise of high-quality map data, using the spatial connection relationship of road sections for extraction. In actual situations, the quality of the acquired data is uneven, and the spatial connection relationship of the road network is difficult to guarantee. Especially in the case of multiple breakpoints, it is even more impractical to extract the road network topology structure using the spatial connection relationship of road sections. In addition, for large 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 a method and system for automatically extracting complex road network topological relationships in a multi-breakpoint situation, which solves the technical problem that the prior art cannot effectively utilize the spatial connection relationship of road sections in a multi-breakpoint situation, resulting in inconvenience in extracting the road network topological structure.

[0004] A method for automatically extracting topological relations of a complex road network under multiple breakpoints, comprising:

[0005] The road segments of the road network data are split, and the split road segments are traversed to determine the breakpoints and record the target adjustment lines corresponding to the breakpoints. Then, the road network data is converted into an undirected graph according to the breakpoints and the corresponding target adjustment lines. The undirected graph is then divided into connected subgraphs. A base line is selected in the connected subgraph and the nodes of other lines are projected onto the base line. The coordinates of the nodes are adjusted according to the projection positions of all projected nodes on the base line to obtain the adjusted road network data, and the topological relationship is regenerated according to the adjusted road network data.

[0006] Furthermore, the traversing of the split road sections to determine the breakpoints and the target adjustment lines corresponding to the breakpoints includes:

[0007] By visiting each coordinate point of a line within the specified range to see if there are other lines in the same direction, we can determine whether the coordinate point of the current line needs to be adjusted; if there are other lines in the same direction within the specified range of the coordinate point of the current line, we will select the line closest to it and record its number as the target adjustment line of the breakpoint, and continue to visit until all the coordinate points of all sections have been visited. The specified range is within 1m.

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

[0009] If the node projection position is located in the area outside the starting point of the base line, the node coordinates are modified to the coordinates of the starting point of the base line; if the node projection position is located in the area outside the end point of the base line, the node coordinates are modified to the coordinates of the end point of the base line; if the node projection position is located in the area corresponding to the base line, the distance between the node projection position and the starting point and end point of the base line is further determined, and the node coordinates are modified to the coordinates that are closer to the two.

[0010] Furthermore, the regeneration of the topological relationship based on the adjusted road network data includes: deduplicating the longitude and latitude coordinates of the starting and ending points of all road sections 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 sections, and each longitude and latitude coordinate is uniquely numbered; based on the node numbering, according to the longitude and latitude coordinates of the starting and ending points of the road section, obtaining the connection node number of the road section, thereby realizing the construction of the road network topology.

[0011] Furthermore, the split road section only includes a starting point and an end point.

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

[0013] Furthermore, the nodes in the undirected graph are road sections, and the edges of the undirected graph indicate that a breakpoint exists in one of the two road sections and can be adjusted to the other road section.

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

[0015] A system for automatically extracting complex road network topology relations under multi-breakpoint conditions, used to implement a method for automatically extracting complex road network topology relations under multi-breakpoint conditions, comprising: 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 sections of the road network data, traverse the split road sections, determine the breakpoints and record the target adjustment straight lines corresponding to the breakpoints;

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

[0018] The coordinate adjustment module is used to adjust the coordinates of the nodes according to the projection positions of all projection nodes on the base line to obtain 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 determine the breakpoints and corresponding target adjustment lines, then integrate the target adjustment lines by projection, adjust the line node coordinates according to the line node projection positions, and finally regenerate the topological relationship according to the adjusted line node coordinates, thereby being able to extract the topological relationship of a large-scale road network in the case of low-quality road network data, lowering the threshold for extracting road network topological relationships and greatly saving labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a flowchart of a method for automatically extracting complex road network topology relationships under multiple breakpoints in an embodiment of the present application.

[0022] Figure 2 The LineString data format of the straight line involved in the embodiment of the present application is displayed.

[0023] Figure 3 These are possible breakpoint types involved in the embodiments of the present application.

[0024] Figure 4 These are possible breakpoint types involved in the embodiments of the present application.

[0025] Figure 5 The projection area is divided according to the embodiment of the present application. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application for protection, 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 making creative work belong to the scope of protection of the present application.

[0027] A method for automatically extracting topological relations of complex road networks with multiple breakpoints, such as Figure 1 As shown, including:

[0028] The original road network vector data, i.e., the road network data, is obtained, and the road segments of the road network data are split, i.e., all the road segments LineString in the road network are split, and the split road segments are traversed, breakpoints are determined, and the target adjustment lines corresponding to the breakpoints are recorded, and then the road network data is converted into an undirected graph according to the breakpoints and the corresponding target adjustment lines, and then the undirected graph is divided into connected subgraphs, a base line is selected in the connected subgraph, and then the nodes of other lines are projected onto the base line, and the coordinates of the nodes are adjusted according to the projection positions of all the projected nodes on the base line to obtain the adjusted road network data, and the topological relationship is regenerated according to the adjusted road network data.

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

[0030] In actual road vector data, there are many possible breakpoint situations. Figure 3 , 4 Shows the common types of breakpoints in the data.

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

[0032] By visiting each coordinate point of a line to see if there are other lines with the same direction within the specified range, it is determined whether the coordinate point of the current line needs to be adjusted; if there are other lines with the same direction within the specified range of the coordinate point of the currently visited line, the closest line is selected and its number is recorded as the target adjustment line for the breakpoint, and the visit is continued until all the coordinate points of all sections are visited.

[0033] In this embodiment, the specified range refers to within 1m. Specifically, whether there are other lines with the same direction within 1m around each coordinate point of the current straight line A (excluding the line with a distance of 0) is determined to determine whether the coordinate point of the current straight line is a breakpoint.

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

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

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

[0037] If the node projection position is located outside the starting point of the base line, the node coordinates are modified to the starting point coordinates of the base line; if the node projection position is located outside the end point of the base line, the node coordinates are modified to the end point coordinates of the base line; if the node projection position is located in the area corresponding to the base line, the distance between the node projection position and the starting point and end point of the base line is further determined, and the node coordinates are modified to the coordinates that are closer to the two. After the node coordinates are adjusted, the starting and ending coordinates of all sections with the node as the starting point or end point are updated.

[0038] In this embodiment, if Figure 5 As shown, the projection position on the base line is divided into an area head beyond the starting point of the base line, an area tail beyond the end point of the base line, and an area within corresponding to the base line.

[0039] In another embodiment, the regenerating the topological relationship based on the adjusted road network data includes: deduplicating the longitude and latitude coordinates of the starting and ending points of all road sections 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 sections, and each longitude and latitude coordinate is uniquely numbered; based on the node numbering, according to the longitude and latitude coordinates of the starting and ending points of the road section, obtaining the connection node number of the road section, thereby realizing the construction of the road network topology.

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

[0041] In another embodiment, the base straight line is the straight line with the longest 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 a breakpoint exists in one of the two road segments and can be adjusted to the other road segment.

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

[0044] In another embodiment, it also relates to a system for automatically extracting complex road network topology relations under multiple breakpoint conditions, which is used to implement a method for automatically extracting complex road network topology relations under multiple breakpoint conditions, 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 straight line confirmation module is used to split the road sections of the road network data, traverse the split road sections, determine the breakpoints and record the target adjustment straight lines corresponding to the breakpoints;

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

[0047] The coordinate adjustment module is used to adjust the coordinates of the nodes according to the projection positions of all projection nodes on the base line to obtain 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, it also includes a data acquisition module for acquiring original road network vector data.

[0050] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A method for automatically extracting topological relations of complex road networks with multiple breakpoints, characterized in that: include: The road segments of the road network data are split, and the split road segments are traversed to determine the breakpoints and record the target adjustment lines corresponding to the breakpoints. Then, the road network data is converted into an undirected graph according to the breakpoints and the corresponding target adjustment lines. The undirected graph is then divided into connected subgraphs. A base line is selected from the connected subgraph and the nodes of other lines are projected onto the base line. The coordinates of the nodes are adjusted according to the projection positions of all projected nodes on the base line to obtain the adjusted road network data, and the topological relationship is regenerated according to the adjusted road network data.

2. According to the method for automatically extracting complex road network topology relations under multiple breakpoints in claim 1, it is characterized in that: The traversing of the split road sections to determine the breakpoints and the target adjustment lines corresponding to the breakpoints includes: By visiting each coordinate point of a line to see if there are other lines with the same direction within the specified range, it is determined whether the coordinate point of the current line needs to be adjusted; if there are other lines with the same direction within the specified range of the coordinate point of the currently visited line, the closest line is selected and its number is recorded as the target adjustment line for the breakpoint, and the visit is continued until all the coordinate points of all sections are visited.

3. The method for automatically extracting complex road network topology relations under multiple breakpoints according to claim 1 is characterized in that: The step of adjusting the node coordinates of all straight lines according to the projection position includes: If the node projection position is located in the area outside the starting point of the base line, the node coordinates are modified to the coordinates of the starting point of the base line; if the node projection position is located in the area outside the end point of the base line, the node coordinates are modified to the coordinates of the end point of the base line; if the node projection position is located in the area corresponding to the base line, the distance between the node projection position and the starting point and end point of the base line is further determined, and the node coordinates are modified to the coordinates that are closer to the two.

4. The method for automatically extracting complex road network topology relations under multiple breakpoints according to claim 1 is characterized in that: The regeneration of the topological relationship based on the adjusted road network data includes: removing duplications from the longitude and latitude coordinates of the starting and ending points of all road sections 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 sections, and each longitude and latitude coordinate is uniquely numbered; based on the node numbering, according to the longitude and latitude coordinates of the starting and ending points of the road section, obtaining the connection node number of the road section to realize the construction of the road network topology.

5. The method for automatically extracting complex road network topology relations under multiple breakpoints according to claim 1 is characterized in that: The split road segment only includes a starting point and an end point.

6. The method for automatically extracting complex road network topology relations under multiple breakpoints according to claim 1 is characterized in that: The base straight line is the straight line with the longest length in the connected subgraph.

7. The method for automatically extracting complex road network topology relations under multiple breakpoints according to claim 1 is characterized in that: The nodes in the undirected graph are road sections, and the edges of the undirected graph indicate that there is a breakpoint in one of the two road sections and that the breakpoint can be adjusted to the other road section.

8. The method for automatically extracting complex road network topology relations under multiple breakpoints according to claim 1 is characterized in that: The connected subgraph indicates that the road segments in the subgraph can be merged into one road segment.

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