A method and system for generating 3D scenes from 2D GIS vector data

Abstract

The present invention provides a method and system for generating 3D scenes from two-dimensional GIS vector data, which specifically includes the following steps: a client uploads two-dimensional GIS vector data of a building surface to a server; the server receives the data and performs a format standardization operation on the data; performs topological processing on the standardized building surface data, converts complex polygons in the building surface into simple polygons; reads the vertex array of the simple polygon, and constructs the building surface into a three-dimensional geometric body; if there is an attribute value of a mapping type in the building surface data, obtains the corresponding mapping to perform a tiling operation, otherwise reads the default mapping to perform a tiling operation; combines the three-dimensional geometric body and the material after the tiling operation to form a mesh object, and adds it to the 3D scene. The present invention obtains the two-dimensional GIS vector data of the building surface, automatically pulls up and maps it according to the height information of each building surface data, and then adds it to the three-dimensional scene, thereby solving the problem of low efficiency caused by manual comparison of CAD drawing data or manual modeling.

Description

Technical Field

[0001] The present invention relates to three-dimensional modeling technology, and in particular to a method and system for generating a 3D scene from two-dimensional GIS vector data. Background Art

[0002] With the development of technology, the traditional two-dimensional GIS map display method can no longer meet the user's demand for visual experience. The three-dimensional GIS scene allows people to browse map data from a 720-degree full-view angle, greatly improving the user experience. However, most of the current three-dimensional scene modeling relies on manual modeling, which is modeled by modeling software such as 3DSMax. The production cost of three-dimensional data is high, and the update and maintenance also require professional modeling personnel, which is inefficient and not convenient for the rapid and intuitive presentation of data. Summary of the invention

[0003] In view of the defects existing in the prior art, the purpose of the present invention is to provide a method and system for generating 3D scenes from two-dimensional GIS vector data, which solves the problem that most of the current three-dimensional scene modeling relies on manual modeling and modeling through modeling software such as 3DSMax. The production cost of three-dimensional data is high, and updating and maintenance also require professional modeling personnel, which is inefficient and not convenient for rapid and intuitive presentation of data.

[0004] In order to achieve the above object, the specific technical solution adopted by the present invention is as follows:

[0005] A method for generating a 3D scene from two-dimensional GIS vector data, specifically comprising the following steps:

[0006] S1, the client uploads the 2D GIS vector data of the building surface to the server;

[0007] S2, after the server receives the data, if the format of the data is not the set format, the format of the data is converted to the set format to ensure the format standardization of all two-dimensional GIS vector data;

[0008] S3, performing topological processing on the standardized building surface data, converting complex polygons in the building surface into simple polygons, so as to ensure that all building surfaces are simple polygons;

[0009] S4, reads the vertex array of simple polygons and constructs the building surface into a three-dimensional geometry;

[0010] S5, determining whether there is a map type attribute value in the building surface data, if so, obtaining the corresponding map according to the building type to which the building surface belongs and performing a tiling operation, otherwise reading a default map and performing a tiling operation;

[0011] S6, combining the 3D geometry and the tiled material to form a mesh object, and adding it to the 3D scene.

[0012] Preferably, the step S3 of converting the complex polygons in the building surface into simple polygons specifically refers to

[0013] Determine whether there are complex polygons in the building surface. Complex polygons have non-fixed intersections or a vertex shares several edges. If there are complex polygons, use the triangle cutting algorithm to perform topological processing on the complex polygons and convert the complex polygons into simple polygons.

[0014] Preferably, step S4 reads the vertex array of simple polygons and constructs the building surface into a three-dimensional geometric body. Specifically,

[0015] Read the simple polygon vertex array, and according to the height attribute field in the array, pull the two-dimensional figure into a three-dimensional figure with the corresponding height value, copy the two two-dimensional figures as the bottom and top surfaces, and merge the bottom surface, the pulled side surface, and the top surface into a three-dimensional geometric body.

[0016] Preferably, step S4 reads the vertex array of simple polygons and constructs the building surface into a three-dimensional geometric body. Specifically,

[0017] Read the simple polygon vertex array and record it as v1, set the vertex Z-axis value to 0, copy the vertex array and record it as v2; traverse the vertex array of v2, set the height value of the building surface as the Z coordinate, traverse the two arrays of v1 and v2, and form triangular faces according to adjacent indexes. Two triangular faces form a face, which is the three-dimensional figure of the side; convert the two vertex arrays into a two-dimensional plane, merge the bottom face, the pulled side face, and the top face to form a geometric body.

[0018] Preferably, step S5 specifically refers to

[0019] Determine whether there is an attribute value of the map type in the building surface data. The attribute value is assigned by the user according to the building type pre-set by the server. If so, get the corresponding map according to the building type to which the building surface belongs to perform the tiling operation. Otherwise, read the default map to perform the tiling operation, that is, use the same map globally for tiling operations.

[0020] A system for generating 3D scenes from two-dimensional GIS vector data, comprising a client and a server, wherein the client is used for a user to upload two-dimensional GIS vector data of a building surface to the server;

[0021] The server is used to, after receiving the data, convert the format of the data into the set format if the format is not a set format, so as to ensure the standardization of the format of all two-dimensional GIS vector data; perform topological processing on the standardized building surface data, convert the complex polygons in the building surface into simple polygons, so as to ensure that all building surfaces are simple polygons; read the vertex array of the simple polygon, and construct the building surface into a three-dimensional geometric body; determine whether there is a map type attribute value in the building surface data, and if so, obtain the corresponding map according to the building type to which the building surface belongs to perform a tiling operation, otherwise read the default map to perform a tiling operation; combine the three-dimensional geometric body and the material after the tiling operation to form a mesh object, and add it to the 3D scene.

[0022] Preferably, converting complex polygons in the building surface into simple polygons specifically refers to

[0023] Determine whether there are complex polygons in the building surface. Complex polygons have non-fixed intersections or a vertex shares several edges. If there are complex polygons, use the triangle cutting algorithm to perform topological processing on the complex polygons and convert the complex polygons into simple polygons.

[0024] Preferably, reading the vertex array of simple polygons and constructing the building surface into a three-dimensional geometric body specifically refers to

[0025] Read the simple polygon vertex array, and according to the height attribute field in the array, pull the two-dimensional figure into a three-dimensional figure with the corresponding height value, copy the two two-dimensional figures as the bottom and top surfaces, and merge the bottom surface, the pulled side surface, and the top surface into a three-dimensional geometric body.

[0026] Preferably, reading the vertex array of simple polygons and constructing the building surface into a three-dimensional geometric body specifically refers to

[0027] Read the simple polygon vertex array and record it as v1, set the vertex Z-axis value to 0, copy the vertex array and record it as v2; traverse the vertex array of v2, set the height value of the building surface as the Z coordinate, traverse the two arrays of v1 and v2, and form triangular faces according to adjacent indexes. Two triangular faces form a face, which is the three-dimensional figure of the side; convert the two vertex arrays into a two-dimensional plane, merge the bottom face, the pulled side face, and the top face to form a geometric body.

[0028] Preferably, it is determined whether there is an attribute value of the map type in the building surface data, and the attribute value is assigned by the user through the client according to the building type pre-set by the server. If so, the corresponding map is obtained according to the building type to which the building surface belongs to perform a tiling operation, otherwise the default map is read to perform a tiling operation, that is, the same map is used globally for tiling operations.

[0029] The beneficial effect of the present invention is that a method is proposed to automatically generate a model of geographic basic elements through a program, by obtaining two-dimensional GIS vector data of building surfaces, and automatically pulling and mapping the data according to the height information of each building surface, and then adding it to the three-dimensional scene, thereby solving the problem of low efficiency caused by manual comparison of CAD drawing data or manual modeling in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 It is a flow chart of a method for generating 3D scene from two-dimensional GIS vector data of the present invention;

[0032] FIG. 2 is a schematic diagram of a complex polygon and a simple polygon;

[0033] FIG3 is a schematic diagram of an embodiment of constructing a side surface of a three-dimensional geometric body;

[0034] Figure 4 It is a principle block diagram of a system that generates 3D scenes from two-dimensional GIS vector data. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0036] The English title of the present invention is explained below:

[0037] Shapefile is an open standard spatial data format in the geographic information software industry.

[0038] GeoJson is a format for encoding various geographic data structures and a geographic spatial information data exchange format based on JavaScript Object Notation (JSON).

[0039] GeoTools: An open source JavaGIS toolkit.

[0040] Three.js: A webGL framework.

[0041] ExtrudeGeometry: A tool for stretching two-dimensional graphics to form three-dimensional graphics.

[0042] like Figure 1 As shown, the present invention proposes a method for generating a 3D scene from two-dimensional GIS vector data, which specifically includes the following steps:

[0043] S1, the client uploads the two-dimensional GIS vector data of the building surface to the server; the format of the two-dimensional GIS vector data is not limited. The present invention takes Shapeflie file or GeoJson file as an example, and the user uploads the Shapeflie file or GeoJson file of the building surface through the client.

[0044] S2, after the server receives the data, if the format of the data is not the set format, the format of the data is converted to the set format to ensure the format standardization of all two-dimensional GIS vector data;

[0045] Specifically, the setting format in the present invention is a GeoJson file. If the user uploads a building surface Shapeflie file through the client, the Shapefile file is converted into a GeoJson file through the open source SDK-GeoTools to maintain the standardization of the data.

[0046] S3, performing topological processing on the standardized building surface data, converting complex polygons in the building surface into simple polygons, so as to ensure that all building surfaces are simple polygons;

[0047] Specifically, the conversion of complex polygons in the building surface into simple polygons in step S3 specifically refers to

[0048] Determine whether there are complex polygons in the building surface. Complex polygons have non-fixed intersections or a vertex shares several edges. If there are complex polygons, use the triangle cutting algorithm to perform topological processing on the complex polygons and convert the complex polygons into simple polygons.

[0049] A building face is an irregular simple polygon, that is, it should be composed of a set of ordered vertices, and each vertex is shared by only two edges, and all intersections of the edges are vertices. Figure 2a The polygons in are simple polygons. Figure 2b The polygon is considered a complex polygon because the intersection of edges 0-2 and 1-3 is not a vertex. Figure 2cThe polygon is also determined to be a complex polygon because vertex 1 shares four edges. Therefore, in order to solve the problem of complex polygons that may exist in the data, the most commonly used triangle cutting algorithm "ear cutting method" is used for topological processing to convert complex polygons into simple polygons.

[0050] S4, reads the vertex array of simple polygons and constructs the building surface into a three-dimensional geometric body; the following two methods are illustrated:

[0051] (1) Step S4 reads the vertex array of simple polygons and constructs the building surface into a three-dimensional geometric body. Specifically,

[0052] Read the simple polygon vertex array, use the ExtrudeGeometry method in three.js, and according to the height attribute field in the array, stretch the two-dimensional figure into a three-dimensional figure with the corresponding height value, copy the two two-dimensional figures as the bottom and top surfaces, and merge the bottom surface, the stretched side surface, and the top surface into a three-dimensional geometric body.

[0053] (2) Step S4 reads the vertex array of simple polygons and constructs the building surface into a three-dimensional geometric body. Specifically,

[0054] Read the simple polygon vertex array and record it as v1. The three-dimensional space coordinates of the vertex are X, Y, and Z. Set the Z-axis value of the vertex to 0. Copy the vertex array and record it as v2. Traverse the vertex array of v2 and set the height value of the building surface to the Z coordinate, such as Figure 3a As shown, A2, B2, and C2 have the building height as the Z coordinate value, traverse the two arrays v1 and v2, and form triangular faces according to the adjacent indexes, such as Figure 3b As shown, A1, A2, and B2 form a triangular face, and two triangular faces form a face. Figure 3c As shown, A2, B2, and B1 form a triangular face, which together with the previous triangular face form a plane, namely the three-dimensional figure of the side; the two vertex arrays are converted into a two-dimensional plane, and the bottom face, the pulled side face, and the top face are merged to form a geometric body.

[0055] S5, determining whether there is a map type attribute value in the building surface data, if so, obtaining the corresponding map according to the building type to which the building surface belongs and performing a tiling operation, otherwise reading a default map and performing a tiling operation;

[0056] Specifically, determine whether there is an attribute value of the map type in the building surface data. The attribute value is assigned by the user according to the building type pre-set by the server, such as "school", "shopping mall", "factory", "high-rise building", etc. If so, obtain the corresponding map according to the building type to which the building surface belongs and perform the tiling operation. The platform provides multiple sets of maps of corresponding styles. Otherwise, read the default map to perform the tiling operation, that is, use the same map globally for tiling operations.

[0057] S6, combining the 3D geometry and the tiled material to form a mesh object, and adding it to the 3D scene.

[0058] Specifically, the constructed geometry is combined with the textured material to form a mesh object in Three.js, and finally the mesh object is added to the Three.js scene to achieve the same visualization effect as loading the building model.

[0059] In other embodiments, the server can dynamically model the texture according to the parameterized rules and the building type to obtain the actual exterior images of schools, shopping malls, factories, and high-rise buildings. The basic idea of ​​the parameterized rules specifically refers to obtaining the basic units of the actual exterior image through subdivision, such as several independent sub-modules such as glass, doors, windows, and billboards. The splitting operation is repeated until the position cannot be decomposed. The quantitative information of the actual exterior image is parameterized and assigned different numerical values ​​in order to obtain a texture of the required size and shape of the building surface, which is convenient for later calls and the texture can be replaced by adjusting the parameters.

[0060] like Figure 4 As shown, the present invention proposes a system for generating 3D scenes from two-dimensional GIS vector data, including a client and a server, wherein the client is used for users to upload two-dimensional GIS vector data of building surfaces to the server; the format of the two-dimensional GIS vector data is not limited, and the present invention takes Shapeflie files or GeoJson files as examples, and users upload Shapeflie files or GeoJson files of building surfaces through the client.

[0061] After receiving the data, if the format of the data is not the set format, the server converts the format of the data into the set format to ensure the standardization of the format of all two-dimensional GIS vector data; specifically, the set format in the present invention is a GeoJson file. If the user uploads a building surface Shapeflie file through the client, the Shapefile file is converted into a GeoJson file through the open source SDK-GeoTools to maintain the standardization of the data. Perform topological processing on the standardized building surface data, convert the complex polygons in the building surface into simple polygons to ensure that all building surfaces are simple polygons; read the vertex array of simple polygons, and construct the building surface into a three-dimensional geometric body; determine whether there is a map type attribute value in the building surface data, if so, obtain the corresponding map according to the building type to which the building surface belongs to perform a tiling operation, otherwise read the default map to perform a tiling operation; combine the three-dimensional geometric body and the material after the tiling operation to form a mesh object, and add it to the 3D scene.

[0062] Preferably, converting complex polygons in the building surface into simple polygons specifically refers to

[0063] Determine whether there are complex polygons in the building surface. Complex polygons have non-fixed intersections or a vertex shares several edges. If there are complex polygons, use the triangle cutting algorithm to perform topological processing on the complex polygons and convert the complex polygons into simple polygons.

[0064] A building face is an irregular simple polygon, that is, it should be composed of a set of ordered vertices, and each vertex is shared by only two edges, and all intersections of the edges are vertices. Figure 2a The polygons in are simple polygons. Figure 2b The polygon is considered a complex polygon because the intersection of edges 0-2 and 1-3 is not a vertex. Figure 2c The polygon is also determined to be a complex polygon because vertex 1 shares four edges. Therefore, in order to solve the problem of complex polygons that may exist in the data, the most commonly used triangle cutting algorithm "ear cutting method" is used for topological processing to convert complex polygons into simple polygons.

[0065] Preferably, reading the vertex array of simple polygons and constructing the building surface into a three-dimensional geometric body specifically refers to

[0066] Read the simple polygon vertex array, use the ExtrudeGeometry method in three.js, and according to the height attribute field in the array, stretch the two-dimensional figure into a three-dimensional figure with the corresponding height value, copy the two two-dimensional figures as the bottom and top surfaces, and merge the bottom surface, the stretched side surface, and the top surface into a three-dimensional geometric body.

[0067] Preferably, reading the vertex array of simple polygons and constructing the building surface into a three-dimensional geometric body specifically refers to

[0068] Read the simple polygon vertex array and record it as v1, set the vertex Z axis value to 0, copy the vertex array and record it as v2; traverse the vertex array of v2, and set the height value of the building surface to the Z coordinate, such as Figure 3a As shown, A2, B2, and C2 have the building height as the Z coordinate value, traverse the two arrays v1 and v2, and form triangular faces according to the adjacent indexes, such as Figure 3b As shown, A1, A2, and B2 form a triangular face, and two triangular faces form a face. Figure 3c As shown, A2, B2, and B1 form a triangular face, which together with the previous triangular face form a plane, namely the three-dimensional figure of the side; the two vertex arrays are converted into a two-dimensional plane, and the bottom face, the pulled side face, and the top face are merged to form a geometric body.

[0069] Preferably, it is determined whether there is an attribute value of the map type in the building surface data, and the attribute value is assigned by the user through the client according to the building type pre-set by the server. If so, the corresponding map is obtained according to the building type to which the building surface belongs to perform a tiling operation, otherwise the default map is read to perform a tiling operation, that is, the same map is used globally for tiling operations.

[0070] In other embodiments, the server can dynamically model the texture according to the parameterized rules and the building type to obtain the actual exterior images of schools, shopping malls, factories, and high-rise buildings. The basic idea of ​​the parameterized rules specifically refers to obtaining the basic units of the actual exterior image through subdivision, such as several independent sub-modules such as glass, doors, windows, and billboards. The splitting operation is repeated until the position cannot be decomposed. The quantitative information of the actual exterior image is parameterized and assigned different numerical values ​​in order to obtain a texture of the required size and shape of the building surface, which is convenient for later calls and the texture can be replaced by adjusting the parameters.

[0071] The beneficial effects of the present invention are as follows: the present invention relates to the field of Internet digital twins, and proposes a method for automatically generating models of basic geographic elements through a program. By obtaining the shapefile file of the building surface, according to the height information of each planar geographic data, the model is automatically pulled up and mapped and added to the three.js three-dimensional scene. Compared with the prior art, most house models rely on comparing CAD drawing data or manual modeling, which reduces the time investment in this part of modeling and improves the model loading efficiency.

[0072] With the above-mentioned ideal embodiments of the present invention as inspiration, through the above-mentioned description, those skilled in the art can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for generating a 3D scene from two-dimensional GIS vector data, characterized in that: The specific steps include: S1, the client uploads the 2D GIS vector data of the building surface to the server; S2, after the server receives the data, if the format of the data is not the set format, the format of the data is converted to the set format to ensure the format standardization of all two-dimensional GIS vector data; S3, performing topological processing on the standardized building surface data, converting complex polygons in the building surface into simple polygons, so as to ensure that all building surfaces are simple polygons; S4, reads the vertex array of simple polygons and constructs the building surface into a three-dimensional geometry; S5, determining whether there is a map type attribute value in the building surface data, if so, obtaining the corresponding map according to the building type to which the building surface belongs and performing a tiling operation, otherwise reading a default map and performing a tiling operation; S6, combining the 3D geometry and the tiled material to form a mesh object, and adding it to the 3D scene; Step S4 reads the vertex array of simple polygons and constructs the building surface into a three-dimensional geometric body. Read the simple polygon vertex array and record it as v1, set the vertex Z-axis value to 0, copy the vertex array and record it as v2; traverse the vertex array of v2, set the height value of the building surface as the Z coordinate, traverse the two arrays of v1 and v2, and form triangular faces according to adjacent indexes. Two triangular faces form a face, which is the three-dimensional figure of the side; convert the two vertex arrays into a two-dimensional plane, merge the bottom face, the pulled side face, and the top face to form a geometric body.

2. The method for generating a 3D scene from two-dimensional GIS vector data according to claim 1, characterized in that: The conversion of complex polygons in the building surface into simple polygons in step S3 specifically refers to Determine whether there are complex polygons in the building surface. Complex polygons have non-fixed intersections or a vertex shares several edges. If there are complex polygons, use the triangle cutting algorithm to perform topological processing on the complex polygons and convert the complex polygons into simple polygons.

3. The method for generating a 3D scene from two-dimensional GIS vector data according to claim 1, characterized in that: Step S4 reads the vertex array of simple polygons and constructs the building surface into a three-dimensional geometric body. Read the simple polygon vertex array, and according to the height attribute field in the array, pull the two-dimensional figure into a three-dimensional figure with the corresponding height value, copy the two two-dimensional figures as the bottom and top surfaces, and merge the bottom surface, the pulled side surface, and the top surface into a three-dimensional geometric body.

4. The method for generating a 3D scene from two-dimensional GIS vector data according to claim 1, characterized in that: Step S5 specifically refers to Determine whether there is an attribute value of the map type in the building surface data. The attribute value is assigned by the user according to the building type pre-set by the server. If so, get the corresponding map according to the building type to which the building surface belongs to perform the tiling operation. Otherwise, read the default map to perform the tiling operation, that is, use the same map globally for tiling operations.

5. A system for generating 3D scenes from 2D GIS vector data, characterized in that: It includes a client and a server, wherein the client is used for users to upload two-dimensional GIS vector data of building surfaces to the server; After receiving the data, the server is used to convert the format of the data into the set format if the format of the data is not the set format, so as to ensure the standardization of the format of all two-dimensional GIS vector data; perform topological processing on the standardized building surface data, convert the complex polygons in the building surface into simple polygons, so as to ensure that all building surfaces are simple polygons; read the vertex array of the simple polygon, and construct the building surface into a three-dimensional geometric body; Determine whether there is a map type attribute value in the building surface data. If so, obtain the corresponding map according to the building type to which the building surface belongs and perform the tiling operation. Otherwise, read the default map and perform the tiling operation. Combine the 3D geometry and the material after the tiling operation to form a mesh object, and add it to the 3D scene. Read the vertex array of simple polygons and construct the building surface into a three-dimensional geometry. Read the simple polygon vertex array and record it as v1, set the vertex Z-axis value to 0, copy the vertex array and record it as v2; traverse the vertex array of v2, set the height value of the building surface as the Z coordinate, traverse the two arrays of v1 and v2, and form triangular faces according to adjacent indexes. Two triangular faces form a face, which is the three-dimensional figure of the side; convert the two vertex arrays into a two-dimensional plane, merge the bottom face, the pulled side face, and the top face to form a geometric body.

6. The system for generating 3D scenes from 2D GIS vector data according to claim 5, characterized in that: Converting complex polygons in building faces into simple polygons specifically refers to Determine whether there are complex polygons in the building surface. Complex polygons have non-fixed intersections or a vertex shares several edges. If there are complex polygons, use the triangle cutting algorithm to perform topological processing on the complex polygons and convert the complex polygons into simple polygons.

7. The system for generating 3D scenes from 2D GIS vector data according to claim 5, characterized in that: Read the vertex array of simple polygons and construct the building surface into a three-dimensional geometry. Read the simple polygon vertex array, and according to the height attribute field in the array, pull the two-dimensional figure into a three-dimensional figure with the corresponding height value, copy the two two-dimensional figures as the bottom and top surfaces, and merge the bottom surface, the pulled side surface, and the top surface into a three-dimensional geometric body.

8. The system for generating 3D scenes from 2D GIS vector data according to claim 5, characterized in that: Determine whether there is an attribute value of the map type in the building surface data. The attribute value is assigned by the user through the client according to the building type pre-set by the server. If so, get the corresponding map according to the building type to which the building surface belongs to perform the tiling operation, otherwise read the default map to perform the tiling operation, that is, use the same map globally for tiling operations.

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