Method for automatically dividing urban grids based on ear cutting method

Abstract

The invention relates to a method for automatically dividing urban grids based on an ear cutting method. The method is characterized in that an ear cutting method algorithm is adopted, and regular urban grids are automatically divided by analyzing and processing urban geographical boundaries. According to the adjustable parameter setting method, the system can be flexibly adjusted according to geographic features, scales and specific application requirements of different cities. Accurate grid division can be realized by adjusting parameters for mountainous cities with complex terrains or regular plain cities. And urban planning and management requirements in various scenes can be met by automatically switching functions according to different requirements. For example, during emergency response, the system can be automatically switched to a finer grid division mode, so that the rescue efficiency is improved; when macroscopic city planning is carried out, a large-scale grid mode can be switched, and overall layout analysis is facilitated.

Description

Technical Field

[0001] The invention belongs to the field of geographic information system and urban planning, and in particular relates to a method for automatically dividing urban grids based on ear-cutting algorithm. Background Art

[0002] Existing urban grid division methods include: 1) Manual division method Description: Traditional urban grid division mainly defines the starting grid according to the (0, 0) position point of the grid, and then manually divides and numbers the grids around it; Advantages: It can take into account the specific needs and special circumstances of the city and has a certain degree of flexibility; Disadvantages: Inefficient, susceptible to individual errors, and difficult to achieve large-scale and efficient grid division.

[0003] 2) GIS-based mapping tools Description: Using geographic information system (GIS) technology, urban data is processed and analyzed through software tools to achieve preliminary grid division, and then the unnecessary boundary grids are manually confirmed again; this method can process a large amount of geographic data, but it still requires human participation; Advantages: Compared with pure manual methods, it improves the degree of automation and efficiency to a certain extent; Disadvantages: It is necessary to manually determine the unnecessary boundary grids again.

[0004] Existing technical solutions have obvious limitations in terms of automation, efficiency, accuracy and adaptability of urban grid division. These methods often fail to meet the high-precision and high-efficiency requirements of modern urban planning and resource management for grid division. In addition, existing technologies often lack sufficient flexibility and adaptability when dealing with complex geographical features and changing urban planning needs. Summary of the invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a technical solution for a method for automatically dividing urban grids based on the ear-cut method, which significantly improves the automation, efficiency, accuracy and adaptability of urban grid division by introducing advanced algorithms and automation technologies.

[0006] The method for automatically dividing a city grid based on the ear-cutting algorithm is characterized in that the ear-cutting algorithm is used to automatically divide a regular city grid by analyzing and processing the city's geographical boundaries, and specifically includes the following steps: 1) Obtain the city geographic boundary data from the GIS map and obtain a set of continuous longitude and latitude data of the boundary; 2) Then, the obtained boundary longitude and latitude array is preprocessed, and the ear-cutting algorithm is used to gradually cut out triangles starting from a point on the boundary until the entire boundary is completely divided into a triangular mesh; 3) Then enter the longitude and latitude of the grid origin, which is the (0, 0) grid, the size of each grid, and the longitude and latitude information of the diagonal of the large rectangle to be divided; 4) According to the input origin information and the size of each grid, pre-generate grid numbers, rectangular longitude and latitude of the grid and other information for the large range rectangle to be divided; 5) Traverse each mesh and determine whether the four vertices of the mesh are within the divided triangular mesh; if all four vertices are within the triangular mesh, the mesh is completely within the region; if at least one point is within the triangular mesh, it intersects with the region and belongs to the boundary mesh; if none of the four vertices are within the triangular mesh, the mesh does not belong to the region.

[0007] The method for automatically dividing a city grid based on the ear-cutting algorithm is characterized in that the ear-cutting algorithm in step 2) is as follows: 2.1) Get all the vertex data of the polygon. The vertices need to be composed in a certain order, with clockwise or counterclockwise continuous vertex data, and build a bidirectional linked list; 2.2) Count all the concave and convex points by vector cross product and check whether the internal angle is greater than 180 degrees; 2.3) Determine whether the remaining points are within a triangle and calculate all the ears; 2.4) Each time a triangle is constructed with the ear as the vertex for culling, each culling is a triangle sequence; 2.5) When the number of remaining vertices is 3, triangulation is complete.

[0008] The advantages of the present invention are as follows: 1. Strong adaptability The adjustable parameter setting method enables the system to be flexibly adjusted according to the geographical characteristics, size and specific application requirements of different cities. Whether it is a mountainous city with complex terrain or a relatively regular plain city, accurate grid division can be achieved by adjusting the parameters.

[0009] The automatic switching function according to different needs can meet the needs of urban planning and management in various scenarios. For example, in emergency response, the system can automatically switch to a finer grid division mode to improve rescue efficiency; when conducting macro-urban planning, it can switch to a larger scale grid mode to facilitate overall layout analysis.

[0010] 2. High flexibility It can adapt to different data sources and formats. Whether it is data obtained from the geographic information system database or data obtained through channels such as satellite images, it can be effectively processed and analyzed to provide accurate basic data for urban grid division.

[0011] Changes and updates to city boundaries can be responded to quickly and adjusted accordingly without the need for large-scale redesign and development, saving time and costs.

[0012] 3. Efficient and accurate The algorithm based on the ear-cut method can efficiently triangulate the city's geographic boundaries, greatly improving the speed of mesh division. At the same time, the optimized algorithm can ensure the accuracy of the division and avoid unreasonable mesh shapes and sizes.

[0013] The automated process reduces the errors and uncertainties caused by manual intervention and improves the quality and reliability of meshing.

[0014] 4. Innovative Applications The ear-cut method is innovatively applied to the field of urban grid division, bringing new technical ideas and methods to this field. This innovative application not only improves the efficiency and accuracy of grid division, but also provides a reference for the technical development of other related fields. Compared with traditional urban grid division methods, it has obvious advantages and competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Flowchart of the ear cutting algorithm of the present invention. DETAILED DESCRIPTION

[0016] The present invention will be further described below in conjunction with the accompanying drawings: The present invention adopts the ear-cutting algorithm to automatically divide a regular urban grid by analyzing and processing the urban geographical boundaries, and specifically includes the following steps: 1) Obtain the city geographic boundary data from the GIS map and obtain a set of continuous longitude and latitude data of the boundary; 2) Then, the obtained boundary longitude and latitude array is preprocessed, and the ear-cutting algorithm is used to gradually cut out triangles starting from a point on the boundary until the entire boundary is completely divided into a triangular mesh; 3) Then enter the longitude and latitude of the grid origin, which is the (0, 0) grid, the size of each grid, and the longitude and latitude information of the diagonal of the large rectangle to be divided; 4) According to the input origin information and the size of each grid, pre-generate grid numbers, rectangular longitude and latitude of the grid and other information for the large range rectangle to be divided; 5) Traverse each mesh and determine whether the four vertices of the mesh are within the divided triangular mesh; if all four vertices are within the triangular mesh, the mesh is completely within the region; if at least one point is within the triangular mesh, it intersects with the region and belongs to the boundary mesh; if none of the four vertices are within the triangular mesh, the mesh does not belong to the region.

[0017] Step 2) The algorithm of the middle ear cutting method is as follows: 2.1) Get all the vertex data of the polygon. The vertices need to be arranged in a certain order, clockwise or counterclockwise continuous vertex data (can be obtained directly from the GIS service), and build a bidirectional linked list; 2.2) Count all the concave and convex points by vector cross product and check whether the internal angle is greater than 180 degrees; 2.3) Determine whether the remaining points are within a triangle and calculate all the ears; 2.4) Each time a triangle is constructed with the ear as the vertex for culling, each culling is a triangle sequence; 2.5) When the number of remaining vertices is 3, triangulation is complete.

[0018] The key points of the present invention include: 1.1. Innovative algorithm application: The key is to innovatively apply the ear-cut algorithm to the field of automatic urban grid division. As a mature polygon triangulation algorithm, the ear-cut method has been limited in its application in fields such as urban planning. This proposal cleverly adjusts and optimizes the ear-cut method to enable it to triangulate urban geographic boundaries efficiently and accurately, laying the foundation for subsequent grid division.

[0019] The ear-cutting method can automatically process various complex shapes of urban boundaries, adapt to the unique geographical characteristics of different cities, and overcome the difficulties of traditional methods in dealing with complex boundaries.

[0020] 1.2.Automated process: A complete set of automated processes from data acquisition and preprocessing to ear-cutting algorithm execution and then to grid adjustment has been established, which reduces manual intervention and improves division efficiency and accuracy.

[0021] 1.3. Adaptability and flexibility: The system is highly adaptable and flexible, and can be adjusted according to different urban planning needs and grid size requirements. By setting different parameters, urban grids of different accuracy and scale can be generated to meet the needs of different application scenarios.

[0022] For example, in emergency management, finer grids can be generated to improve response speed; in macro-urban planning, larger-scale grids can be generated for overall layout analysis.

[0023] The innovative features of the present invention are as follows: 2.1. Algorithm uniqueness: The specific application mode and parameter setting of the ear-cut method in urban grid division ensure that other competitors cannot easily copy or imitate the optimization and adjustment of the ear-cut method in the present invention, so as to maintain the technical advantage of the present invention in the field of urban grid division.

[0024] It includes the starting point selection strategy of the ear cutting method, the order and rules of triangle cutting, and the methods for dealing with special geographical features.

[0025] 2.2. Adaptable technical solutions: The technical solution of the present invention makes the system adaptable and flexible, for example, adjustable parameter setting method and automatic switching according to different needs.

Claims

1. A method for automatically dividing urban grids based on ear cutting algorithm, characterized in that The ear-cutting algorithm is used to automatically divide the city grid into regular grids by analyzing and processing the city's geographical boundaries. The specific steps include the following: 1) Obtain the city geographic boundary data from the GIS map and obtain a set of continuous longitude and latitude data of the boundary; 2) Then, the obtained boundary longitude and latitude array is preprocessed, and the ear-cutting algorithm is used to gradually cut out triangles starting from a point on the boundary until the entire boundary is completely divided into a triangular mesh; 3) Then enter the longitude and latitude of the grid origin, which is the (0, 0) grid, the size of each grid, and the longitude and latitude information of the diagonal of the large rectangle to be divided; 4) According to the input origin information and the size of each grid, pre-generate grid numbers, rectangular longitude and latitude of the grid and other information for the large range rectangle to be divided; 5) Traverse each mesh and determine whether the four vertices of the mesh are within the divided triangular mesh; if all four vertices are within the triangular mesh, the mesh is completely within the region; if at least one point is within the triangular mesh, it intersects with the region and belongs to the boundary mesh; if none of the four vertices are within the triangular mesh, the mesh does not belong to the region.

2. The method for automatically dividing urban grids based on the ear-cutting algorithm according to claim 1 is characterized in that The algorithm of the middle ear cutting method in step 2) is as follows: 2.1) Get all the vertex data of the polygon. The vertices need to be composed in a certain order, with clockwise or counterclockwise continuous vertex data, and build a bidirectional linked list; 2.2) Count all the concave and convex points by vector cross product and check whether the internal angle is greater than 180 degrees; 2.3) Determine whether the remaining points are within a triangle and calculate all the ears; 2.4) Each time a triangle is constructed with the ear as the vertex for culling, each culling is a triangle sequence; 2.5) When the number of remaining vertices is 3, triangulation is complete.

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