Method and System for Deriving Road Edge Lines Based on Road Surface Polygons

Abstract

The present invention discloses a method and system for deriving road sidelines based on road surface polygons, which obtain a road surface polygon point set and a road vector point set from high-precision map road data; extract a road surface polygon vertex point set from the road surface polygon point set, calculate the vertex heading based on the road surface polygon vertices, extract the point closest to the corresponding road surface polygon vertex from the road vector point set and set it as the road vector base point, and calculate the vector heading based on the road vector base point; judge and identify the heading direction of the road surface polygon sidelines corresponding to the respective vertices according to the difference between the vertex heading and the corresponding vector heading; combine the same-direction edges into one single side, and combine the opposite-direction edges into the other single side to form the two sidelines of the road; thereby deriving a roadside line that is more matched to the road surface, and the derived road sidelines can obtain the elevation level relationship of the corresponding road surface, and can more accurately derive the road sidelines that can be used to construct the elevation.

Description

Technical Field

[0001] The present invention relates to high-precision road scene production technology, and in particular to a method and system for deriving road sidelines based on road surface polygons. Background Art

[0002] Currently, the road sidelines in use are collected separately. During the data collection process, the road surface data and the roadside lines cannot be directly associated due to processing methods. Moreover, the collected results of the road sideline data are a single long piece of data and do not correspond one-to-one with the data of multiple road surfaces that have been collected. When deriving the elevation of the road surface based on the road vector and the road surface data, since the data collected from the road surface and the data of the road sidelines are not directly associated, there is no way to map the hierarchical relationship carried by the road surface data to the road sidelines. As a result, during the subsequent map rendering process, there are differences between the rendering results based on the roadside lines and the rendered road surface, and errors will occur when deriving and using elevation data in the original way. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above technical deficiencies, and propose a method and system for deriving road sidelines based on road surface polygons, so as to solve the problem that the road sidelines and the road surface data in existing high-precision road data cannot be associated and matched.

[0004] To achieve the above technical purpose, the first aspect of the technical solution of the present invention provides a method for deriving road sidelines based on road surface polygons, which includes the following steps:

[0005] Obtain the road surface polygon point set and the road vector point set from the high-precision map road data;

[0006] Extract the road surface polygon vertex point set from the road surface polygon point set, calculate the vertex heading based on the road surface polygon vertices, extract the point closest to the corresponding road surface polygon vertex from the road vector point set and set it as the road vector base point, and calculate the vector heading based on the road vector base point;

[0007] Judge and identify the heading direction of the road surface polygon sidelines corresponding to the respective vertices according to the difference between the vertex heading and the corresponding vector heading;

[0008] Combine the same-direction sides into one single side, and combine the opposite-direction sides into the other single side to form the two side lines of the road.

[0009] The second aspect of the present invention provides a system for deriving road sidelines based on road surface polygons, which includes the following functional modules:

[0010] A point set acquisition module, configured to obtain the road surface polygon point set and the road vector point set from the high-precision map road data;

[0011] A heading calculation module, configured to extract a set of vertex points of a road surface polygon from a set of road surface polygon points, calculate vertex headings based on the vertex points of the road surface polygon, extract, from a set of road vector points, a point closest to a corresponding vertex point of the road surface polygon as a road vector base point, and calculate a vector heading based on the road vector base point;

[0012] A heading determination module, configured to determine and identify the heading direction of a road surface polygon side corresponding to a corresponding vertex based on the difference between the vertex heading and the corresponding vector heading;

[0013] A side line fusion module, configured to combine same-direction sides into one single side and combine opposite-direction sides into another single side to form two side lines of a road.

[0014] A third aspect of the present invention provides a server, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above method for deriving road side lines based on a road surface polygon is implemented.

[0015] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the above method for deriving road side lines based on a road surface polygon is implemented.

[0016] Compared with the prior art, the method and system for deriving road side lines based on a road surface polygon according to the present invention derive a roadside line that better matches the road surface through the road surface polygon and the road vector. Compared with the original roadside line acquisition and usage method, the road side line derived by the present invention can obtain the elevation level relationship of the corresponding road surface, which is used to more accurately derive the road side line that can be used to construct the elevation. And after the elevation derivation is completed, it can be directly used to construct road surface data, and finally data slicing is performed for 3D rendering. Description of the Drawings

[0017] Figure 1 is a flowchart of a method for deriving road side lines based on a road surface polygon according to an embodiment of the present invention;

[0018] Figure 2 is a schematic diagram of a road surface polygon for high-precision map road data acquisition;

[0019] Figure 3 is a schematic diagram of a road side line and a road surface polygon derived by using a method for deriving road side lines based on a road surface polygon according to an embodiment of the present invention;

[0020] Figure 4 is another flowchart of a method for deriving road side lines based on a road surface polygon according to an embodiment of the present invention;

[0021] Figure 5 It is a module block diagram of a system for deriving road boundaries based on pavement polygons according to an embodiment of the present invention;

[0022] Figure 6 It is another module block diagram of a system for deriving road boundaries based on pavement polygons according to an embodiment of the present invention. Specific implementation manners

[0023] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] As Figures 1 to 3 shown, an embodiment of the present invention provides a method for deriving road boundaries based on pavement polygons, which includes the following steps:

[0025] S1. Obtain a pavement polygon point set and a road vector point set from high-precision map road data.

[0026] The high-precision map road data includes a lot of information, such as pavement polygon point set information, road vector point set information, road ID information, road length information, etc. Therefore, the pavement polygon point set and the road vector point set can be directly obtained from the high-precision map road data.

[0027] S2. Extract a pavement polygon vertex point set from the pavement polygon point set, calculate the vertex heading according to the pavement polygon vertices, extract the point closest to the corresponding pavement polygon vertex from the road vector point set and set it as the road vector base point, and calculate the vector heading according to the road vector base point.

[0028] As the pavement polygon is Figure 2 shown, according to the magnitude of the forward and backward heading deflection angles of the pavement polygon points, a pavement polygon vertex point set is extracted from the pavement polygon point set; let the heading angle A1 calculated by the current pavement polygon point and the previous pavement polygon point, and the heading angle A2 calculated by the next pavement polygon point to the current pavement polygon point, then the forward and backward heading angle deflection angle B of the pavement polygon point = A2 - A1. If the forward and backward heading deflection angle of the pavement polygon point is greater than the vertex heading angle setting threshold, it is determined as a pavement polygon vertex; if the forward and backward heading deflection angle of the pavement polygon point is less than the vertex heading angle setting threshold, it is determined as a pavement polygon ordinary point.

[0029] Specifically, the calculation formula of the heading angle is as follows:

[0030] A = arctan(sin(γ2 - γ1) * cos(δ2), cos(δ1) * sin(δ2) - sin(δ1) * cos(δ2) * cos(γ2 - γ1))

[0031] * cos(γ2 - γ1))

[0032] In the above formula, A is the course angle, γ1 is the starting longitude of the road surface polygon point, δ1 is the starting latitude of the road surface polygon point, γ2 is the ending longitude of the road surface polygon point, and δ2 is the ending latitude of the road surface polygon point.

[0033] After extracting the vertex point set of the road surface polygon, configure the corresponding mapping table between the road surface polygon vertices and the road surface polygon side lines. In the mapping table, the road surface polygon side line corresponding to the road surface polygon vertex is the side line connecting the road surface polygon vertex and the next road surface polygon vertex.

[0034] The vertex course calculated according to the road surface polygon vertex is specifically calculated according to the road surface polygon vertex and its next general point of the road surface polygon; that is, the course angle between the road surface polygon vertex and its next general point of the road surface polygon is the vertex course.

[0035] Find the point closest to the road surface polygon vertex from the road vector point set and set it as the road vector base point. Calculate the vector course according to the road vector base point and the next general point of the road vector point set in the order of the road vector point set; that is, the course angle between the road vector base point and the next general point of the road vector point set in the order of the road vector point set is the vector course.

[0036] Among them, to find the point closest to the vertex of the road surface polygon from the road vector point set, its calculation formula is as follows:

[0037] S = R·arc cos[cosβ1cosβ2cos(α1 - α2) + sinβ1sinβ2]

[0038] In the above formula, S is the distance, β1 is the latitude angle of the road surface polygon vertex, α1 is the longitude angle of the road surface polygon vertex, β2 is the latitude angle of the road vector point, α2 is the longitude angle of the road vector point, and R is the radius of the earth.

[0039] S3. Judge and identify the course direction of the road surface polygon side line corresponding to the corresponding vertex according to the difference between the vertex course and the corresponding vector course.

[0040] Specifically, preset the same - direction course difference range and the reverse - direction course difference range;

[0041] Compare the vertex heading and the corresponding vector heading. If the heading difference falls within the same-direction heading difference range, the current edge is determined to be a same-direction edge; if the heading difference falls within the opposite-direction heading difference range, the current edge is determined to be an opposite-direction edge; if the heading difference does not fall within either the same-direction heading difference range or the opposite-direction heading difference range, the current edge is determined to be an edge in other directions.

[0042] When an edge in other directions is parsed, if the previous and next edges parsed are both same-direction edges, then this edge in other directions is classified into the same-direction edges; if the previous and next edges parsed are both opposite-direction edges, then this edge in other directions is classified into the opposite-direction edges; if one of the previous and next edges parsed is a same-direction edge and the other is an opposite-direction edge, it is discarded and not calculated.

[0043] S4. Combine the same-direction edges into one single-side edge, and combine the opposite-direction edges into the other single-side edge to form the two side edges of the road.

[0044] Specifically, combine the same-direction edges and the edges in other directions between multiple same-direction edges into one single-side edge, and combine the opposite-direction edges and the edges in other directions between multiple opposite-direction edges into the other single-side edge to form the two side edges of the road, as Figure 3 shown.

[0045] Derive a roadside line that better matches the road surface from the road surface polygon. Compared with the original roadside line collection and usage method, the road edge lines derived by the present invention can obtain the elevation level relationship of the corresponding road surface, which is used to more accurately derive the road edge lines that can be used to construct the elevation. And after the elevation derivation is completed, it can be directly used to construct the road surface data, and finally data slicing is performed for 3D rendering.

[0046] However, to further eliminate the interference of the zigzag headings in the vertex set of the road surface polygon on the edge line derivation, as Figure 4 shown, the present invention further includes step S5, and the step S5 includes the following contents:

[0047] S5. Real-time calculate the difference in the lengths of the two side edges of the road. If the difference exceeds 10% of the road surface length, the aggregation point set method needs to be used to abstractly analyze the vertices of the polygon to eliminate the interference of the zigzag headings in the vertex set of the road surface polygon on the edge line derivation.

[0048] Among them, by using the third-party library shapely to import the edge lines, the lengths of the road edge lines can be obtained, and according to the road ID, the road surface length can be extracted from the high-precision map road data.

[0049] The use of the aggregation point set method to abstractly analyze the vertices of the polygon specifically includes:

[0050] Aggregate the vertices of the road surface polygon according to a preset aggregation distance to form multiple vertex aggregation point sets;

[0051] Calculate the headings of the vertex aggregation point set and its adjacent vertices before and after;

[0052] Preset an anti-interference heading range value, and determine whether to simplify the vertex aggregation point set according to the comparison result between the headings of the vertex aggregation point set and its adjacent vertices before and after and the preset anti-interference heading range value;

[0053] Rededuct the two side lines of the road according to the simplified pavement polygon vertex point set.

[0054] Specifically, since the multiple headings formed by points at close distances are likely to cause errors in analyzing the side line headings, resulting in a serrated shape in the pavement data during the acquisition process. Therefore, in the present invention, the pavement polygon vertices at close distances are aggregated into a vertex aggregation point set. In the vertex aggregation point set, the vertices are still arranged in the order of the original pavement polygon point set. Because the heading distances within the vertex aggregation point set are too close, the vertex aggregation point set can be regarded as a whole for calculation and deduction. Compare the heading between the vertex aggregation point set and the previous adjacent vertex with the heading between the vertex aggregation point set and the next adjacent vertex. Specifically, compare the heading from the previous adjacent vertex to the first vertex of the vertex aggregation point set with the heading from the last point of the vertex aggregation point set to the next adjacent vertex. If the heading difference does not exceed 20 degrees, it is considered that the change in the front and rear heading angles passing through this point set is not significant, and thus it is considered that the sides before and after the vertex aggregation point set are approximately in the same direction and can be determined to be the same side. The side lines inside the vertex aggregation point set can be directly connected to the previous side line and the next side line, achieving the elimination of the interference of the serrated headings in the point set on the side line deduction; thereby deducing and eliminating the interference points to obtain the correct road side lines.

[0055] As Figure 5 shown, an embodiment of the present invention also discloses a system for deducing road side lines based on a pavement polygon, which includes the following functional modules:

[0056] Point set acquisition module 10, configured to acquire a pavement polygon point set and a road vector point set from high-precision map road data;

[0057] Heading calculation module 20, configured to extract a pavement polygon vertex point set from the pavement polygon point set, calculate the vertex headings according to the pavement polygon vertices, extract the point closest to the corresponding pavement polygon vertex from the road vector point set as the road vector base point, and calculate the vector heading according to the road vector base point;

[0058] Heading judgment module 30, configured to judge and identify the heading direction of the pavement polygon side line corresponding to the corresponding vertex according to the difference between the vertex heading and the corresponding vector heading;

[0059] The side-line fusion module 40 is configured to combine the same-direction sides into a single side and the opposite-direction sides into another single side to form the two side-lines of the road.

[0060] Correspondingly, as Figure 6 shown, the system for deriving road side-lines based on a road surface polygon according to the present invention further includes a side-line optimization module 50. The side-line optimization module 50 is configured to calculate in real time the difference in the lengths of the two side-lines of the road. If the difference exceeds 10% of the length of the road surface, the aggregation point set method needs to be used to abstractly analyze the vertices of the polygon to exclude the interference of the zigzag headings in the vertex set of the road surface polygon on the derivation of the side-lines.

[0061] The implementation manner of the system for deriving road side-lines based on a road surface polygon in this embodiment is basically the same as the above-mentioned method for deriving road side-lines based on a road surface polygon, so details will not be elaborated here.

[0062] The server in this embodiment is a device that provides computing services, usually referring to a computer with relatively high computing power and provided to multiple consumers through a network. The server in this embodiment includes: a memory, a processor, and a system bus. The memory includes a runnable program stored thereon. Those skilled in the art can understand that the structure of the terminal device in this embodiment does not constitute a limitation on the terminal device, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0063] The memory can be used to store software programs and modules. The processor executes various functional applications and data processing of the terminal by running the software programs and modules stored in the memory. The memory may mainly include a program storage area and a data storage area. Among them, the program storage area can store an operating system, application programs required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area can store data created according to the use of the terminal (such as audio data, phone book, etc.). In addition, the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0064] A runnable program for a method of deriving road side-lines based on a road surface polygon is included in the memory. The runnable program can be divided into one or more modules / units. The one or more modules / units are stored in the memory and executed by the processor to complete the process of information acquisition and implementation. The one or more modules / units can be a series of computer program instruction segments capable of completing specific functions, and these instruction segments are used to describe the execution process of the computer program in the server. For example, the computer program can be divided into a point set acquisition module 10, a heading calculation module 20, a heading judgment module 30, and a side-line fusion module 40.

[0065] The processor is the control center of the server. It connects various parts of the entire terminal device through various interfaces and circuits. By running or executing software programs and / or modules stored in the memory, and by calling the data stored in the memory, it executes various functions of the terminal and processes data, thereby monitoring the terminal as a whole. Optionally, the processor may include one or more processing units; preferably, the processor may integrate an application processor and a modem processor. Among them, the application processor mainly processes the operating system, application programs, etc., and the modem processor mainly processes wireless communication. It can be understood that the above-mentioned modem processor may not be integrated into the processor either.

[0066] The system bus is used to connect various functional components inside the computer. It can transmit data information, address information, and control information. Its types can be, for example, PCI bus, ISA bus, VESA bus, etc. The instructions of the processor are transmitted to the memory through the bus, and the memory feeds back data to the processor. The system bus is responsible for the data and instruction interaction between the processor and the memory. Of course, the system bus can also be connected to other devices, such as network interfaces, display devices, etc.

[0067] The server should at least include a CPU, a chipset, a memory, a disk system, etc. Other components will not be elaborated here.

[0068] In the embodiment of the present invention, the executable program executed by the processor included in the terminal is specifically: a method for deriving road sidelines based on road polygons, which includes the following steps:

[0069] Obtain a road polygon point set and a road vector point set from the high-precision map road data;

[0070] Extract a road polygon vertex point set from the road polygon point set, calculate the vertex heading based on the road polygon vertices, extract the point closest to the corresponding road polygon vertex from the road vector point set and set it as the road vector base point, and calculate the vector heading based on the road vector base point;

[0071] Judge and identify the heading direction of the road polygon sideline corresponding to the corresponding vertex according to the difference between the vertex heading and the corresponding vector heading;

[0072] Combine the same-direction edges into one single side, and combine the opposite-direction edges into the other single side to form the two sidelines of the road.

[0073] Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the above-described systems, devices, and units can refer to the corresponding processes in the foregoing method embodiments, and will not be elaborated here.

[0074] In the above embodiments, the descriptions of the respective embodiments have their own focuses. For parts not detailed or recorded in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0075] Those of ordinary skill in the art can realize that the modules, units, and / or method steps of the respective embodiments described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. A professional technician can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0076] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the respective embodiments of the present invention.

Claims

1. A method for deriving road edges based on road surface polygons, characterized in that The method includes the following steps: Obtain a road surface polygon point set and a road vector point set from high-precision map road data; Extract a road surface polygon vertex point set from the road surface polygon point set, calculate a vertex heading based on the road surface polygon vertices, extract the point closest to the corresponding road surface polygon vertex from the road vector point set as a road vector base point, and calculate a vector heading based on the road vector base point; Judge and identify the heading direction of the road surface polygon side line corresponding to the corresponding vertex according to the difference between the vertex heading and the corresponding vector heading; Combine the same-direction sides into one single side, and combine the opposite-direction sides into the other single side to form the two side lines of the road; The step of extracting a road surface polygon vertex point set from the road surface polygon point set, calculating a vertex heading based on the road surface polygon vertices, extracting the point closest to the corresponding road surface polygon vertex from the road vector point set as a road vector base point, and calculating a vector heading based on the road vector base point specifically includes: Extract a road surface polygon vertex point set from the road surface polygon point set according to the magnitude of the front and rear heading deflection angles of the road surface polygon points; Calculate a vertex heading based on the road surface polygon vertex and its next road surface polygon ordinary point; Find the point closest to the road surface polygon vertex from the road vector point set as a road vector base point, and calculate a vector heading based on the road vector base point and the next road vector ordinary point in the order of the road vector point set located at the road vector base point.

2. The method for deriving a road boundary line based on road surface polygons according to claim 1, wherein, After extracting the road surface polygon vertex point set, configure a corresponding mapping table between the road surface polygon vertices and the road surface polygon side lines. In the mapping table, the road surface polygon side line corresponding to the matching of the road surface polygon vertex is the side line connecting the road surface polygon vertex and the next road surface polygon vertex.

3. The method for deriving road sidelines based on pavement polygons according to claim 1, characterized in that, The step of judging and identifying the heading direction of the road surface polygon side line corresponding to the corresponding vertex according to the difference between the vertex heading and the corresponding vector heading specifically includes: Preset a same-direction heading difference range and an opposite-direction heading difference range; Compare the vertex heading and the corresponding vector heading. If the heading difference falls within the same-direction heading difference range, it is determined that the current side is a same-direction side; if the heading difference falls within the opposite-direction heading difference range, it is determined that the current side is an opposite-direction side; if the heading difference does not fall within the same-direction heading difference range and the opposite-direction heading difference range, it is determined that the current side is a side in other direction; When parsing a side in other direction, if the previous and next sides parsed are both same-direction sides, then this side in other direction is classified into the same-direction sides; if the previous and next sides parsed are both opposite-direction sides, then this side in other direction is classified into the opposite-direction sides; if one of the previous and next sides parsed is a same-direction side and the other is an opposite-direction side, then it is discarded and not calculated.

4. The method for deriving a road edge based on a road surface polygon according to claim 1, wherein The step of combining the same-direction sides into one single side and combining the opposite-direction sides into the other single side to form the two side lines of the road specifically includes: Combine the same-direction sides and the sides in other direction between multiple same-direction sides into one single side, and combine the opposite-direction sides and the sides in other direction between multiple opposite-direction sides into the other single side to form the two side lines of the road.

5. The method for deriving road sidelines based on road surface polygons according to claim 1, characterized in that The method for deriving road side lines based on road surface polygons further includes: Calculate the difference in the lengths of the two side lines of the road in real time. If the difference exceeds 10% of the road surface length, the aggregation point set method needs to be used to abstractly analyze the vertices of the polygon, and eliminate the interference of the zigzag headings in the vertex set of the road surface polygon on the derivation of the side lines.

6. The method for deriving a road boundary line based on road surface polygons according to claim 5, wherein, The use of the aggregation point set method to abstractly analyze the vertices of the polygon specifically includes: Aggregate the vertices of the road surface polygon according to a preset aggregation distance to form multiple vertex aggregation point sets; Calculate the headings of the vertex aggregation point set and its adjacent vertices before and after; Preset an anti-interference heading range value, and judge whether to simplify the vertex aggregation point set according to the comparison result between the headings of the vertex aggregation point set and its adjacent vertices before and after and the preset anti-interference heading range value; Redefine the two side lines of the road according to the simplified vertex set of the road surface polygon.

7. A system for deriving road edges based on road surface polygons, characterized in that, It includes the following functional modules: A point set acquisition module for acquiring a road surface polygon point set and a road vector point set from high-precision map road data; A heading calculation module for extracting a vertex set of the road surface polygon from the road surface polygon point set, calculating the vertex heading according to the vertices of the road surface polygon, extracting the point closest to the corresponding road surface polygon vertex from the road vector point set as the road vector base point, and calculating the vector heading according to the road vector base point; A heading judgment module for judging and identifying the heading direction of the side line of the road surface polygon corresponding to the corresponding vertex according to the difference between the vertex heading and the corresponding vector heading; A side line fusion module for combining the same-direction sides into a single side and combining the opposite-direction sides into another single side to form the two side lines of the road; The extraction of the vertex set of the road surface polygon from the road surface polygon point set, the calculation of the vertex heading according to the vertices of the road surface polygon, the extraction of the point closest to the corresponding road surface polygon vertex from the road vector point set as the road vector base point, and the calculation of the vector heading according to the road vector base point; specifically includes: Extract the vertex set of the road surface polygon from the road surface polygon point set according to the magnitude of the front and rear heading deflection angles of the road surface polygon points; Calculate the vertex heading according to the road surface polygon vertex and its next ordinary road surface polygon point; Find the point closest to the road surface polygon vertex in the road vector point set as the road vector base point, and calculate the vector heading according to the road vector base point and the next ordinary road vector point in the road vector point set in the order of the road vector point set.

8. A server, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method for deriving road side lines based on the road surface polygon according to any one of claims 1 to 6.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for deriving road side lines based on the road surface polygon according to any one of claims 1 to 6.

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