Geographic entity geometric center point extraction method and device

Abstract

The invention discloses a geographic entity geometric center point extraction method and device, and relates to the field of geographic entity geometric center point extraction, and the method comprises the steps: calculating the gravity center of a two-dimensional geometric figure of a geographic entity through employing a cut complement method; judging whether the gravity center is in the two-dimensional geometric figure of the geographic entity by using a ray method; if yes, regarding the gravity center as the geometric center of the geographic entity; and if not, constructing a Delaunay triangulation network in the geometric figure boundary region of the geographic entity, and extracting the geometric center of the geographic entity according to the Delaunay triangulation network. According to the method, the geometric center of the two-dimensional geometric figure of the geographic entity in any shape can be accurately calculated.

Description

Technical Field

[0001] The present application relates to the field of extraction of geometric center points of geographic entities, and in particular to a method and device for extracting geometric center points of geographic entities. Background Art

[0002] The geometric center of a geographic entity refers to the center point of a geometric figure that describes the shape of the entity. Mathematically speaking, the geometric center represents the mean of the coordinates of all the points that make up the geometric figure. Different from the geometric center in a purely mathematical sense, the ideal geometric center of a geographic entity of any shape should satisfy the following characteristics: (1) inclusion, i.e., the geometric center should be located within the geometric scope (or spatial domain) of the geographic entity; (2) symmetry, i.e., the geometric scope of the geographic entity is basically symmetrically distributed around the geometric center; and (3) stability, i.e., the calculation of the geometric center is determined by certain mathematical rules.

[0003] Accurately obtaining the geometric center of geographic entities plays an important role in the fields of feature mapping, location retrieval, and map annotation. Since the calculation of geometric center is also a basic problem in analytic geometry, the research on the calculation of geometric center has a long history, especially for point-shaped and line-shaped geometric figures, the calculation of their geometric center is simple, fast, and accurate. However, the calculation of the geometric center of a surface presents a certain complexity. If the geographic entity is assumed to be homogeneous, for a triangular geographic entity, its centroid is its geometric center; for a circular geographic entity, its center of the circle is its geometric center; for an irregular convex polygonal geographic entity, its centroid is its geometric center; for an irregular concave polygonal geographic entity, its calculation is more difficult. The prior art proposes to use the "cut and fill method" to calculate its centroid as its geometric center through integration; the prior art proposes to use the "substitution method" to calculate the centroid of its minimum circumscribed rectangle as its geometric center. However, facing the geographic entities with complex shapes and diverse structures in the real world, the existing methods are difficult to ensure that the calculated geometric center meets the above three characteristics. In some cases, the calculation results will be located outside the geometric figure or the figure is difficult to be symmetrical, such as Figure 1 shown. Summary of the invention

[0004] The purpose of this application is to provide a method and device for extracting the geometric center point of a geographic entity, which can accurately calculate the geometric center of the two-dimensional geometric figure of a geographic entity of any shape.

[0005] To achieve the above objectives, this application provides the following solutions.

[0006] In a first aspect, the present application provides a method for extracting the geometric center point of a geographic entity, comprising the following steps.

[0007] The centroid of the two-dimensional geometric figure of the geographic entity is calculated using the cut-and-fill method.

[0008] The ray method is used to determine whether the center of gravity is inside the two-dimensional geometric figure of the geographic entity.

[0009] If so, the centroid is considered to be the geometric center of the geographic entity.

[0010] If not, a Delaunay triangulation is constructed within the geometric boundary area of ​​the geographic entity, and the geometric center of the geographic entity is extracted based on the Delaunay triangulation.

[0011] In a second aspect, the present application provides a device for extracting the geometric center point of a geographic entity, comprising the following modules.

[0012] The centroid extraction module is used to calculate the centroid of the two-dimensional geometric figures of geographic entities using the cut-and-fill method.

[0013] The geometric center extraction module is used to use the ray method to determine whether the centroid is inside the two-dimensional geometric figure of the geographic entity; if so, the centroid is regarded as the geometric center of the geographic entity; if not, a Delaunay triangulation is constructed within the boundary area of ​​the geometric figure of the geographic entity, and the geometric center of the geographic entity is extracted based on the Delaunay triangulation.

[0014] In a third aspect, the present application provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-mentioned method for extracting the geometric center point of a geographic entity.

[0015] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned method for extracting the geometric center point of a geographic entity.

[0016] In a fifth aspect, the present application provides a computer program product, including a computer program, which implements the above-mentioned method for extracting the geometric center point of a geographic entity when executed by a processor.

[0017] According to the specific embodiments provided in this application, this application discloses the following technical effects.

[0018] The present application provides a method and device for extracting the geometric center point of a geographic entity. First, the centroid of the geographic entity is calculated using the "cut-and-fill method". Second, the centroid is determined based on the "ray method" to determine whether it is inside the geometric figure of the geographic entity. Finally, a boundary-constrained Delaunay triangulation is constructed to correct the position of the geometric center that is not inside the geometric figure of the geographic entity. By combining the characteristics of the centroid and the Delaunay triangulation (i.e., centrality and structure), the geometric center point that satisfies the three characteristics of inclusion, symmetry, and stability can be extracted for any shape of geographic entity. The method of the present application has stronger robustness. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic diagram showing that the geometric center extracted by the existing method provided in an embodiment of the present application is located outside the geometric figure.

[0021] Figure 2 A diagram of the application environment of a method for extracting the geometric center point of a geographic entity provided in one embodiment of the present application.

[0022] Figure 3 A flowchart of a method for extracting the geometric center point of a geographic entity provided in one embodiment of the present application.

[0023] Figure 4 A schematic diagram of an embodiment of the present application providing a geographic entity with a geometric center located outside a geometric figure.

[0024] Figure 5 A schematic diagram of encrypting the boundary nodes of a geographic entity geometric figure provided in one embodiment of the present application.

[0025] Figure 6 A schematic diagram of a boundary-constrained Delaunay triangulation provided in an embodiment of the present application.

[0026] Figure 7 A schematic diagram of geometric center position correction provided in an embodiment of the present application.

[0027] Figure 8 A schematic diagram for comparative analysis of geometric center points extracted by different methods provided in an embodiment of the present application.

[0028] Fig. 9A schematic diagram of the functional modules of a device for extracting the geometric center point of a geographic entity provided in one embodiment of the present application.

[0029] Fig.10 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0031] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0032] The method for extracting the geometric center point of a geographic entity provided in the embodiment of the present application can be applied to Figure 2 In the application environment shown. Among them, the terminal communicates with the server through the network. The data storage system can store the data that the server needs to process. The data storage system can be set up separately, integrated on the server, or placed on the cloud or other servers. The terminal can send the two-dimensional geometric figure of the geographic entity to be processed to the server. After the server receives the two-dimensional geometric figure of the geographic entity, the server uses the cut-and-fill method to calculate the center of gravity of the two-dimensional geometric figure of the geographic entity; the ray method is used to determine whether the center of gravity is inside the two-dimensional geometric figure of the geographic entity; if so, the center of gravity is regarded as the geometric center of the geographic entity; if not, a Delaunay triangulation is constructed in the boundary area of ​​the geometric figure of the geographic entity, and the geometric center of the geographic entity is extracted according to the Delaunay triangulation. The server can feed back the obtained geometric center of the geographic entity to the terminal. In addition, in some embodiments, the method for extracting the geometric center point of the geographic entity can also be implemented separately by the server or the terminal, such as the terminal can directly extract the geometric center point of the geographic entity for the two-dimensional geometric figure of the geographic entity to be processed, or the server can obtain the video to be processed from the data storage system, and extract the geometric center point of the geographic entity for the two-dimensional geometric figure of the geographic entity to be processed.

[0033] The terminal may be, but is not limited to, various desktop computers, laptops, smart phones, tablet computers, IoT devices, and portable wearable devices. The server may be implemented as an independent server or a server cluster consisting of multiple servers, or may be a cloud server.

[0034] In an exemplary embodiment, Figure 3 As shown, a method for extracting the geometric center point of a geographic entity is provided. The method is executed by a computer device, and can be executed by a computer device such as a terminal or a server alone, or can be executed by a terminal and a server together. In the embodiment of the present application, the method is applied to Figure 2 The server in is taken as an example to illustrate, including the following steps 101 to 104.

[0035] Step 101, using the cut-and-fill method to calculate the centroid of the two-dimensional geometric figure of the geographic entity.

[0036] As an example, the two-dimensional geometric figure of the geographic entity may be the shape of the projection surface of the geographic entity.

[0037] Step 102, using the ray method to determine whether the center of gravity is inside the two-dimensional geometric figure of the geographic entity.

[0038] If yes, then execute step 103: regard the centroid as the geometric center of the geographic entity.

[0039] If not, then execute step 104: construct a Delaunay triangulation within the geometric boundary area of ​​the geographic entity, and extract the geometric center of the geographic entity based on the Delaunay triangulation.

[0040] In another exemplary embodiment of the present application, in step 101, the centroid calculation process using the cut-and-fill method is as follows: Considering the complexity of the geometric shape of the geographic entity, the centroid becomes the first choice for calculating its geometric center. According to the theorem of computational geometry, for any polygon with an area of ​​S, it is divided into N non-overlapping, non-overlapping, and seamless sub-areas. Let the area of ​​the jth (1≤j≤N) sub-area be , the center of gravity is , the centroid of the polygon can be obtained using the centroid formula of the plane thin plate , expressed as the following formula.

[0041] (1).

[0042] (2).

[0043] Specifically, considering the triangle area calculation formula and related mathematical theorems, we can derive the general centroid calculation formula for the polygon enclosed by discrete data points. Any polygon with vertices. The vertices of the polygon are , divide the polygon into n-2 triangles, and then obtain the center of gravity coordinates of the polygon based on the area and center of gravity of each triangle , expressed as the following formula.

[0044] (3).

[0045] (4).

[0046] in, The horizontal and vertical coordinates of the center of gravity of a two-dimensional geometric figure representing a geographic entity; The abscissa of the first vertex of the two-dimensional geometric figure representing the geographic entity; , The horizontal coordinates of the i-th and i+1-th vertices of the two-dimensional geometric figure representing the geographic entity; The ordinate of the first vertex of the two-dimensional geometric figure representing the geographic entity; , The ordinates of the ith and i+1th vertices of the two-dimensional geometric figure representing the geographic entity; n represents the number of vertices. Formula (3) and Formula (4) are calculation formulas after discretization, and the sub-region adopts a triangle.

[0047] The above-mentioned “cut and patch method” effectively improves the accuracy and stability of the geometric center. However, for some geographical entities with more complex shapes, the “cut and patch method” still cannot guarantee that the calculated centroid is definitely inside the geometric center. Figure 4 shown.

[0048] Based on the above content, in step 101, the centroid of the two-dimensional geometric figure of the geographic entity is calculated using the cut-and-fill method, which includes the following steps.

[0049] (1) Divide the two-dimensional geometric figure of the geographic entity into a number of triangles.

[0050] (2) Use the area and centroid of each triangle to calculate the centroid of the two-dimensional geometric figure of the geographic entity.

[0051] In another exemplary embodiment of the present application, in step 102, the ray method is used to determine whether the center of gravity is inside the two-dimensional geometric figure of the geographic entity, including the following steps.

[0052] (a1) Draw horizontal scan lines from the centroid of the two-dimensional geometry of the geographic entity.

[0053] (a2) Determining the number of intersections between the horizontal scan line and the two-dimensional geometric boundary of the geographic entity.

[0054] (a3) If the number of intersections is an odd number, the centroid is deemed to be inside the two-dimensional geometric figure of the geographic entity.

[0055] (a4) If the number of intersections is an even number, the centroid is deemed to be outside the two-dimensional geometric figure of the geographic entity, and a Delaunay triangulation is further constructed to correct the position of the geometric center.

[0056] In another exemplary embodiment of the present application, in step 104, a Delaunay triangulation is constructed within the geometric boundary area of ​​the geographic entity, and the geometric center of the geographic entity is extracted based on the Delaunay triangulation, including the following steps.

[0057] (b1) Encrypt the boundary nodes of the two-dimensional geometry of the geographic entity.

[0058] Because the boundary nodes of geographic entity geometry are usually used to describe important morphological features of surface features, such as turning points and intersection points, there are generally few of them. In order to improve the accuracy of subsequent geometric midpoint positions, the nodes on the boundary need to be encrypted. The specific method is: set the encryption step length d, the value of d is usually the length of the shortest arc segment of the feature boundary; use d as the primitive to sample between two nodes to obtain encrypted points, such as Figure 5 shown.

[0059] (b2) Within the geometric boundary area of ​​the geographic entity, the Delaunay triangulation is constructed using the encrypted boundary nodes.

[0060] Establish a Delaunay triangulation. Use the encrypted boundary point set and the geometric boundary of the geographic entity as the limiting edge condition to establish a boundary-constrained Delaunay triangulation, such as Figure 6 shown.

[0061] (b3) Determine the boundary node closest to the centroid and record it as a reference boundary node, and regard the triangle where the reference boundary node is located as a reference triangle.

[0062] Calculate the nearest point to the centroid on the geometric boundary of the geographic entity, and use the triangle where the point is located as the nearest triangle to the centroid.

[0063] (b4) Select multiple triangles within a preset range around the reference triangle and record them as selected triangles.

[0064] Set a certain number of triangle samples N, and select N triangles around the nearest triangle of the centroid as triangles suitable for geometric center calculation.

[0065] (b5) Determine the geometric center of a geographic entity based on multiple selected triangles.

[0066] In another exemplary embodiment of the present application, in step (b5), the areas of the selected N triangles are calculated and the area error range is set. . Select the triangle space with the largest area and the area error value is The two triangles within the range have the center of their shared boundary as the geometric center of the geographic entity; if there is no spatial connection and the area error value is within If there are two triangles within the range, the centroid of the triangle with the largest area is selected as the geometric center of the geographic entity. Figure 7 shown.

[0067] Therefore, in step (b5), determining the geometric center of the geographic entity based on the multiple selected triangles includes: (c1) Calculate the area of ​​each selected triangle and select the triangle with the largest area.

[0068] (c2) Determine whether there is a target triangle; the target triangle is a triangle that is connected to the triangle space with the largest area and whose area error value is within a preset error range.

[0069] (c3) If a target triangle exists, the center of the shared edge between the target triangle and the triangle with the largest area is taken as the geometric center of the geographic entity.

[0070] (c4) If the target triangle does not exist, the centroid of the triangle with the largest area is taken as the geometric center of the geographic entity.

[0071] In this application, how to accurately obtain the geometric center point of the two-dimensional geometric figure of geographic entities with diverse shapes and complex structures has always been a fundamental issue of concern to academia and industry. In view of the shortcomings of the existing methods for calculating geometric center points based on centroids, this application proposes a robust method for extracting the geometric center points of geographic entities. First, the centroid of the geographic entity is calculated using the "cut and fill method"; second, the centroid is determined based on the "ray method" to determine whether it is inside the geometric figure of the geographic entity; finally, a boundary-constrained Delaunay triangulation is constructed to correct the position of the geometric center that is not inside the geometric figure of the geographic entity. By combining the characteristics of the centroid and the Delaunay triangulation (i.e., centrality and structure), the geometric center point that meets the three characteristics of inclusion, symmetry, and stability can be extracted for geographic entities of any shape.

[0072] The following is a verification experiment of the stability and accuracy of the method of the present application.

[0073] 1. Experimental data and environment Relying on the WJ-III map workstation developed by a scientific research institute, the method for extracting the geometric center point of geographic entities proposed in this application is embedded in the C++ environment, and experimental data is used to verify the stability and accuracy. The experimental data is taken from the basic surveying and mapping building geographic entity data produced in a certain area of ​​a city. The buildings in this area have diverse shapes and complex structures, and the geometric features presented by the buildings in the entire area are very representative. The experimental data has a total of 14,559 building entity surface elements.

[0074] 2. Experimental results and analysis (1) Stability analysis After data spatial association and attribute consistency verification, all 14,559 building surface elements in the test area were generated with corresponding geometric center points in a 1:1 format. After spatial overlay analysis, all geometric center points were located within the building surface graphics.

[0075] (2) Accuracy analysis The method of this application is compared with the existing method of calculating the geometric center of geographic entities based on the centroid. According to statistics, among the geometric center points obtained by the two methods, the geometric center points with completely overlapping spatial positions account for 86.23%, and the geometric center points with different spatial positions account for 13.77%. The calculation of the geometric center points of 12 typical geographic entities is selected for visual comparison and analysis, such as Figure 8 shown. Figure 8 In the figure, when the geometric center points overlap, the geometric center points extracted by the two methods are represented by small dots; when the geometric center points do not overlap, the geometric center of the geographic entity obtained by the existing method is represented by a small dot in a circular box, and the geometric center of the geographic entity obtained by the method of the present application is represented by a small dot in a rectangular box.

[0076] Based on the above experimental analysis, it is concluded that for convex polygons, regardless of their simple or complex shapes, the geometric center points obtained by the method of this application and the existing method for calculating the geometric center point based on the center of gravity overlap, and the position of the geometric center point is reasonable; for concave polygons with simple or complex shapes, the geometric center point obtained by the existing method for calculating the geometric center point based on the center of gravity often falls outside the polygon. Compared with the existing method for calculating the geometric center point based on the center of gravity, the geometric center point extracted by the method of this application fully complies with the theoretical characteristics of the geometric center point of inclusion, symmetry, and stability, and exhibits greater robustness.

[0077] The present application also provides an application scenario, which applies the above-mentioned method for extracting the geometric center point of geographic entities. Specifically: the method for extracting the geometric center point of geographic entities provided in this embodiment can be applied in a map annotation scenario. The scenario includes a geographic entity collection link, a geometric center point extraction link and a map annotation link; the geographic entity collection link is used to collect geographic entities required for map annotation; the geometric center point extraction link is used to extract the geometric center of the geographic entity; the map annotation link is used to perform map annotation based on the extracted geometric center. The method for extracting the geometric center point of geographic entities provided in this embodiment belongs to the geometric center point extraction link in the content processing link.

[0078] Based on the same inventive concept, the embodiment of the present application also provides a device for extracting the geometric center point of a geographic entity for implementing the method for extracting the geometric center point of a geographic entity involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more embodiments of the device for extracting the geometric center point of a geographic entity provided below can refer to the limitations of the method for extracting the geometric center point of a geographic entity above, and will not be repeated here.

[0079] In an exemplary embodiment, Fig. 9 As shown, a device for extracting the geometric center point of a geographic entity is provided, comprising the following modules.

[0080] The centroid extraction module M1 is used to calculate the centroid of the two-dimensional geometric figure of the geographic entity using the cut-and-fill method.

[0081] The geometric center extraction module M2 is used to use the ray method to determine whether the centroid is inside the two-dimensional geometric figure of the geographic entity; if so, the centroid is regarded as the geometric center of the geographic entity; if not, a Delaunay triangulation is constructed within the boundary area of ​​the geometric figure of the geographic entity, and the geometric center of the geographic entity is extracted based on the Delaunay triangulation.

[0082] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Fig.10As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store the geometric center point data of geographic entities. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for extracting the geometric center point of a geographic entity is implemented.

[0083] Those skilled in the art will understand that Fig.10 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components. In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0084] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0085] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0086] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0087] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0088] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0089] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0090] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for extracting the geometric center point of a geographic entity, characterized in that: The method for extracting the geometric center point of a geographic entity comprises: Calculate the centroid of two-dimensional geometric figures of geographic entities using the cut-and-fill method; Using the ray method to determine whether the center of gravity is inside the two-dimensional geometric figure of the geographic entity; If so, the centroid is considered to be the geometric center of the geographic entity; If not, a Delaunay triangulation is constructed within the geometric boundary area of ​​the geographic entity, and the geometric center of the geographic entity is extracted based on the Delaunay triangulation.

2. The method for extracting the geometric center point of a geographic entity according to claim 1, characterized in that: The centroid of two-dimensional geometric figures of geographic entities calculated using the cut-and-patch method includes: Divide the two-dimensional geometry of a geographic entity into a number of triangles; Calculate the centroid of a 2D geometric figure of a geographic entity using the area and centroid of each triangle.

3. The method for extracting the geometric center point of a geographic entity according to claim 2, characterized in that: The formula for calculating the centroid of a two-dimensional geometric figure of a geographic entity is: ； ； in, The horizontal and vertical coordinates of the center of gravity of a two-dimensional geometric figure representing a geographic entity; The abscissa of the first vertex of the two-dimensional geometric figure representing the geographic entity; , The horizontal coordinates of the i-th and i+1-th vertices of the two-dimensional geometric figure representing the geographic entity; The ordinate of the first vertex of the two-dimensional geometric figure representing the geographic entity; , The ordinates of the i-th and i+1-th vertices of the two-dimensional geometric figure representing the geographic entity; n represents the number of vertices.

4. The method for extracting the geometric center point of a geographic entity according to claim 1, characterized in that: Determining whether the center of gravity is inside the two-dimensional geometric figure of the geographic entity by using the ray method includes: Draw a horizontal scan line from the center of gravity; Determining the number of intersections of the horizontal scan line with a two-dimensional geometric boundary of a geographic entity; If the number of intersections is an odd number, the centroid is deemed to be inside the two-dimensional geometric figure of the geographic entity; If the number of intersections is an even number, the centroid is considered to be outside the two-dimensional geometry of the geographic entity.

5. The method for extracting the geometric center point of a geographic entity according to claim 1, characterized in that: Constructing a Delaunay triangulation within the geometric boundary area of ​​a geographic entity, and extracting the geometric center of the geographic entity based on the Delaunay triangulation include: Encrypting the boundary nodes of the two-dimensional geometry of the geographic entity; In the geometric boundary area of ​​the geographic entity, the Delaunay triangulation is constructed using the encrypted boundary nodes; Determine a boundary node that is closest to the center of gravity and record it as a reference boundary node, and regard the triangle where the reference boundary node is located as a reference triangle; Select multiple triangles within a preset range around the reference triangle, and record them as selected triangles; Determines the geometric center of a geographic entity based on multiple selected triangles.

6. The method for extracting the geometric center point of a geographic entity according to claim 5, characterized in that: Determining the geometric center of a geographic entity based on multiple selected triangles includes: Calculate the area of ​​each selected triangle and select the triangle with the largest area; Determine whether there is a target triangle; the target triangle is a triangle that is connected to the triangle space with the largest area and whose area error value is within a preset error range; If a target triangle exists, the center of the shared edge between the target triangle and the triangle with the largest area is taken as the geometric center of the geographic entity; If the target triangle does not exist, the centroid of the triangle with the largest area is taken as the geometric center of the geographic entity.

7. A device for extracting the geometric center point of a geographic entity, characterized in that: The device for extracting the geometric center point of a geographic entity comprises: A centroid extraction module is used to calculate the centroid of the two-dimensional geometric figure of the geographic entity using the cut-and-fill method; The geometric center extraction module is used to use the ray method to determine whether the centroid is inside the two-dimensional geometric figure of the geographic entity; if so, the centroid is regarded as the geometric center of the geographic entity; if not, a Delaunay triangulation is constructed within the boundary area of ​​the geometric figure of the geographic entity, and the geometric center of the geographic entity is extracted based on the Delaunay triangulation.

8. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method for extracting the geometric center point of a geographic entity as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for extracting the geometric center point of a geographic entity described in any one of claims 1 to 6 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the method for extracting the geometric center point of a geographic entity described in any one of claims 1 to 6 is implemented.

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