A rapid 3D modeling method for mountain settlements based on topographic maps

Abstract

The present invention discloses a method for rapid three-dimensional modeling of mountain settlements based on a topographic map. The method comprises: obtaining a topographic map and extracting elevation point data, first building surface data, and building annotation data therefrom; generating an irregular triangulated network (TIN) and a digital elevation model (DEM) using the elevation point data; extracting building base elevation information from the DEM and integrating it into the first building surface data to obtain integrated second building surface data; extracting building height information from the building annotation data and integrating it into the second building surface data to obtain integrated third building surface data; performing three-dimensional stretching on the third building surface data based on the base elevation and building height information to generate a three-dimensional building surface; converting the three-dimensional building surface into a building three-dimensional model in an exchange format; and importing the irregular triangulated network and the building three-dimensional model into modeling software to generate a settlement three-dimensional model. The present invention can integrate terrain elevation, building graphics, and building height information in a topographic map, and achieve rapid and refined three-dimensional modeling of mountain settlements through parameterized three-dimensional stretching.

Description

Technical Field

[0001] The present invention relates to the field of spatial information technology, and in particular to a method for rapid three-dimensional modeling of mountain settlements based on topographic maps. Background Art

[0002] The three-dimensional settlement model can provide intuitive, accurate and detailed information about the built environment, and is widely used in spatial planning, display design, traffic management, emergency response and virtual product development.

[0003] There are two main types of existing settlement 3D modeling methods: one is fine modeling using 3D modeling software such as 3DMAX and SketchUp; the other is real-time modeling using 3D measurement technologies such as oblique photography.

[0004] Due to the complex terrain conditions of mountain settlements, different foundation elevations, and densely packed buildings that block each other, the two modeling technologies have shortcomings in modeling mountain settlements: if three-dimensional modeling software is used, the workload is large and time-consuming; if three-dimensional measurement technology is used, the accuracy is often low, and the results are difficult to use for further fine-tuning. Summary of the Invention

[0005] This paper provides a method for rapid 3D modeling of mountain settlements based on topographic maps. This method integrates terrain elevation, building graphics, and building height information from topographic maps, and then achieves rapid and refined 3D modeling of mountain settlements through parametric 3D extrusion. Details are described below:

[0006] A method for rapid three-dimensional modeling of mountain settlements based on a topographic map, the method comprising the following steps:

[0007] Obtaining a topographic map and extracting elevation point data, first building surface data and building annotation data therefrom;

[0008] Generate irregular triangulated networks and digital elevation models using elevation point data;

[0009] Extracting basic elevation information of the building from the digital elevation model and integrating it into the first building surface data to obtain integrated second building surface data;

[0010] Extracting building height information from the building annotation data and integrating it into the second building surface data to obtain integrated third building surface data;

[0011] Perform three-dimensional stretching on the third building surface data according to the foundation elevation and building height information to generate a three-dimensional building surface;

[0012] Converting 3D building surfaces into 3D building models in exchange formats;

[0013] Import the irregular triangulated network and the building 3D model into the modeling software to generate a 3D settlement model.

[0014] The method of obtaining a topographic map and extracting elevation point data, first building surface data and building annotation data therefrom is specifically as follows:

[0015] Obtain a large-scale topographic map CAD file covering the target mountain settlement area;

[0016] Extract the annotation elevation point layer from the topographic map CAD file, save it as an annotation elevation point CAD file, and export the point features as elevation point data in Shapefile format;

[0017] Extract the residential area and facilities layer from the topographic map CAD file, save it as a residential area and facilities CAD file, export the surface elements as the first building surface data in the Shapefile format, and export the building annotations as building annotation data in the Annotation format.

[0018] The method of generating an irregular triangulated network and a digital elevation model using elevation point data is as follows:

[0019] Use the Create TIN tool to input elevation point data and generate an irregular triangulated network;

[0020] Use the TIN to Raster tool to input the irregular triangulated network and generate a digital elevation model of the mountain settlement area.

[0021] The extraction of the building's basic elevation information from the digital elevation model and integration into the first building surface data to obtain the integrated second building surface data is specifically:

[0022] Calculate the center of gravity position of each element in the first building surface data, and generate building center of gravity point data that retains the FID field of the first building surface data;

[0023] The building center point data is spatially superimposed with the digital elevation model, the elevation value of each element of the building center point data is extracted and saved as the building elevation field, and then the building foundation elevation point data with the first building surface data FID field is generated;

[0024] Using the first building surface data FID as the connection field, the building elevation field of the building foundation elevation point data is connected to the first building surface data to generate second building surface data containing foundation elevation information.

[0025] The building height information is extracted from the building annotation data and integrated into the second building surface data to obtain the integrated third building surface data as follows:

[0026] Converting the building annotation data into points to generate first building annotation point data whose attribute table contains the building annotation information;

[0027] Modify the attribute table of the first building annotation point data, create a new building layer number field, extract the number representing the building layer number in the building annotation information as the building layer number field value, assign the building layer number field value of the elements whose building annotation information does not contain numbers to 1, and create a new building height field, making it equal to the product of the building layer number field value and the average floor height of the settlement building, to generate the second building annotation point data;

[0028] Use the Spatial Intersection tool to input the second building annotation point data and the second building surface data to generate the third building annotation point data containing the building height field and the second building surface data FID field;

[0029] Using the second building surface data FID as the connection field, the building height field of the third building annotation point data is connected to the second building surface data to generate the third building surface data containing the building height information.

[0030] The three-dimensional stretching of the third building surface data according to the foundation elevation and building height information to generate the three-dimensional building surface is specifically as follows:

[0031] According to the base elevation value and building height value of each element, the third building surface data is vertically moved and three-dimensionally stretched so that the bottom elevation of the building is equal to the base elevation value and the vertical height is equal to the building height value, thereby generating a three-dimensional building surface.

[0032] The conversion of the three-dimensional building surface into a three-dimensional building model in an exchange format is specifically as follows:

[0033] Use ArcGIS's 3D Layer to Feature Class tool to input the three-dimensional building surface and generate the first building three-dimensional model in the form of a polyhedron; use ArcGIS's Polyhedron to Collada tool to input the first building three-dimensional model and generate the second building three-dimensional model in DAE format.

[0034] The step of importing the irregular triangulated network and the building three-dimensional model into the modeling software to generate the settlement three-dimensional model is as follows:

[0035] Select the corresponding modeling software according to the specific application scenario, import the irregular triangulated network and the building 3D model, generate the settlement 3D model, and then use the settlement 3D model for rendering 3D renderings, processing real-life 3D models, building digital twin villages or traffic simulation and other work scenarios.

[0036] The beneficial effects of the technical solution provided by the present invention are:

[0037] 1. This invention integrates terrain elevation and building height information in topographic maps, rapidly generates surface terrain and batch-extends building elements in a parametric manner, and thus realizes rapid modeling of mountain settlements.

[0038] 2. The surface terrain and three-dimensional building models of the present invention are both exchangeable format files and can be imported into traditional modeling software for further adjustment and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flowchart of the method for rapid 3D modeling of mountain settlements based on topographic maps. DETAILED DESCRIPTION

[0040] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention are described in further detail below.

[0041] In order to make the purpose, technical solutions and advantages of the present invention clearer, the embodiments of the present invention are described in further detail below in conjunction with the accompanying drawings and specific examples. It should be understood that the specific embodiments described herein are only intended to explain the present invention, rather than to limit the present invention. For those skilled in the art, the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present application by illustrating examples of the present invention.

[0042] Due to the complex terrain conditions of mountain settlements, different foundation elevations, and densely packed buildings that block each other, the two currently used modeling technologies have shortcomings in mountain settlement modeling: using 3D modeling software requires a lot of work and takes a long time; while using 3D measurement technology often results in low accuracy and makes it difficult to further fine-tune the results.

[0043] Based on the above background, the embodiment of the present invention uses common topographic maps as raw data, integrates terrain elevation, building graphics and building height information in the topographic maps, and then realizes rapid and refined three-dimensional modeling of mountain settlements through parametric three-dimensional stretching.

[0044] To facilitate understanding of this application, the following terms are explained in the embodiments of the present invention:

[0045] Topographic maps are maps surveyed and mapped by professional organizations according to national and local standards and managed and provided by natural resources departments. This embodiment of the present invention requires the use of large-scale topographic maps, such as 1:500, 1:1000, or 1:2000. According to national standards for the classification of basic geographic elements, topographic maps must include two types of elements: "residential areas and facilities" and "elevation annotation points." The former covers all buildings and their annotation information, while the latter covers all elevation points. In vector topographic maps, these two types of elements are stored in one or more layers.

[0046] Elevation point: a point feature that records the elevation value of a specific location.

[0047] Building surface is a surface element that records the shape and position of the bottom surface of a building.

[0048] Building annotations, which indicate the building structure type and number of floors, consist of both text and numbers. According to national and local standards, large-scale topographic maps should indicate the building structure and number of floors individually, located above the corresponding building. Annotations for single-story buildings may omit the number of floors.

[0049] Digital Elevation Model (DEM) is a physical ground model that represents the ground elevation in the form of a set of ordered numerical arrays. It is a branch of Digital Terrain Model (DTM), and various other terrain characteristic values ​​can be derived from it.

[0050] Triangulated Irregular Network (TIN) is a three-dimensional model that uses connected triangles to fit the earth's surface or other irregular surfaces. It is superior in representing complex surfaces and is widely used in digital mapping, map surface modeling, and other tasks.

[0051] Example 1

[0052] In order to solve the technical problems existing in the background technology, an embodiment of the present invention provides a method for rapid three-dimensional modeling of mountain settlements based on a topographic map, the method comprising the following steps:

[0053] Figure 1 The embodiment of the present invention provides a method for rapid three-dimensional modeling of mountain settlements based on topographic maps. Figure 1 As shown, the method for rapid three-dimensional modeling of mountain settlements based on topographic maps provided by an embodiment of the present invention includes the following steps: S1 to S7.

[0054] S1: Obtain a topographic map and extract elevation point data, first building surface data and building annotation data respectively;

[0055] S2: Generate irregular triangulated network and digital elevation model using elevation point data;

[0056] S3: extracting basic elevation information of the building from the digital elevation model and integrating it into the first building surface data to obtain integrated second building surface data;

[0057] S4: extracting building height information from the building annotation data and integrating it into the second building surface data to obtain integrated third building surface data;

[0058] S5: Perform three-dimensional stretching on the third building surface data according to the foundation elevation and building height information to generate a three-dimensional building surface;

[0059] S6: converting the three-dimensional building surface into a three-dimensional building model in an exchange format;

[0060] S7: Import the irregular triangulated network and the building 3D model into the modeling software for specific application scenarios to generate a 3D settlement model.

[0061] The specific implementation of steps S1 to S7 is described below.

[0062] In a possible implementation, step S1 includes:

[0063] Wherein, step S1 includes:

[0064] S11: Obtain a large-scale topographic map CAD file covering the target mountain settlement area;

[0065] S12: Extract the annotation elevation point layer from the topographic map CAD file and save it as an annotation elevation point CAD file; create a new ArcMap document, set the coordinate system to be consistent with the topographic map CAD file, and load the annotation elevation point CAD file to form an annotation elevation point CAD file layer group (Group Layer); select all the features in the point layer in the annotation elevation point CAD file layer group and export them as elevation point data in Shapefile format;

[0066] S13: extracting the residential area and facilities layer from the topographic map CAD file, saving it as a residential area and facilities CAD file, and loading it into the aforementioned Arcmap document to form a residential area and facilities CAD file layer group; selecting all elements of the surface layer in the residential area and facilities CAD file layer group, and exporting them as first building surface data in Shapefile format;

[0067] S14: Create a new file geodatabase, use the "Import Cad Annotation" tool of ArcGIS to import the annotation layer in the aforementioned residential area and facility CAD file layer group into the aforementioned file geodatabase, and generate building annotation data in Annotation format.

[0068] Wherein, step S2 includes:

[0069] S21: In the aforementioned Arcmap document, use the ArcGIS "Create TIN" tool to input elevation point data to generate a triangulated irregular network (TIN);

[0070] S22: Use the “TIN To Raster” tool in ArcGIS to input the aforementioned irregular triangulated network and generate a digital elevation model of the mountain settlement area.

[0071] Wherein, step S3 includes:

[0072] S31: In the aforementioned Arcmap document, use the “Feature To Point” tool of ArcGIS to input the first building surface data to generate the building center point data;

[0073] Among them, the building center point data uses the new ORIG_FID field to retain the FID field of the first building surface data, and each element in the building center point data is located at the center of gravity position of the corresponding element in the first building surface data.

[0074] S32: Use the ArcGIS "Extract Values ​​to Points" tool to generate building foundation elevation point data using the building centroid data as input point features and the digital elevation model as input raster.

[0075] Among them, the building foundation elevation point data uses the new ORIG_FID field to retain the FID field of the first building surface data, and the newly added "RASTERVALU" field records the elevation value of the center of gravity point of each building surface element.

[0076] S33: Use the "Join Field" tool in ArcGIS, with the first building surface data as the "Input Table", FID as the "Input Join Field", the building foundation elevation point data as the "Join Table", and ORIG_FID as the "Output Join Field". Check RASTERVALU in the "Join Fields" to generate the second building surface data, and change the name of the field "RASTERVALU" to "Foundation Elevation" in ArcCatalog.

[0077] Wherein, step S4 includes:

[0078] S41: In the aforementioned Arcmap document, use the “Feature To Point” tool of ArcGIS to input the building annotation data to generate first building annotation point data;

[0079] Among them, the "Text" field of the first building annotation point data is in the "text + number" or "text only" format, which records the structure and number of floors of the building. The "text only" format defaults to the number of floors of the building being 1.

[0080] S42: export the attribute table of the first building annotation point data, convert it into ANSI code, save it as a CSV file and open it with EXCEL, create new columns of "Number of Building Floors" and "Building Height"; use regular expressions to extract the value of the "Text" column in each row as the cell value of "Number of Building Floors" in the same row; if the "Text" column content in a row does not contain a number, assign the cell value of "Number of Building Floors" in that row to 1; calculate the cell value of "Building Height" to make it equal to the product of the cell value of "Number of Building Floors" in the same row and the general floor height of the settlement building (for example, 3 meters); save it as an XLS file after the modification is completed; use the "Table To Table" tool of ArcGIS, input the XLS file, choose to keep all fields, and generate a DBF file; use the DBF file to replace the original dbf file of the first building annotation point data, thereby modifying the attribute table of the annotation point data and generating the second building annotation point data;

[0081] Among them, the average floor height of settlement buildings is influenced by local traditions and varies from place to place, generally around 3 meters; the second building annotation point data includes a "building height" field.

[0082] S43: using the “Intersect” tool of ArcGIS, inputting the second building surface data and the second building annotation point data to generate the third building annotation point data;

[0083] Among them, the third building annotation point data includes "building height", and the "FID_second building surface" field is used to retain the FID field of the second building surface data.

[0084] S44: Use the "Join Field" tool of ArcGIS, with the second building surface data as the "Input Table", FID as the "Input Join Field", the third building annotation point data as the "Join Table", and "FID_Second Building Surface" as the "Output Join Field". In the "Join Fields", check "Number of Building Floors" and "Building Height" to generate the third building surface data.

[0085] Among them, the third building surface data includes fields such as "foundation elevation" and "building height".

[0086] Among them, step S5 includes: creating a new ArcScene document, setting the coordinate system to be consistent with the topographic map CAD file, loading the third building surface data, opening the Layer Properties dialog box, selecting "Use a constant value or expression" under the "Base Height" tab, and entering the expression [base elevation]; checking "Extrude features in layer" under the "Extrusion" tab, entering the expression [building height], selecting "adding it to each feature's base height" for the extrusion method, and generating a three-dimensional building surface after application.

[0087] Wherein, step S6 includes:

[0088] S61: In the aforementioned ArcScene document, use the “Layer 3D to Feature Class” tool of ArcGIS to input the 3D building surface and generate a first 3D building model in the form of a polyhedron;

[0089] S62: Using the “Multipatch To Collada” tool of ArcGIS, the first building 3D model is input to generate a second building 3D model in DAE format;

[0090] Step S7 includes: loading the TIN and the second building three-dimensional model into modeling software for different application scenarios such as 3dMAX to generate a settlement three-dimensional model.

[0091] In summary, the present invention utilizes common topographic maps as raw data, integrating terrain elevation, building graphics, and building height information within the maps. This allows for rapid and refined 3D modeling of mountain settlements through parametric 3D extrusion. The resulting 3D modeling can then be imported into traditional modeling software for further refinement and application. For example, the 3D settlement model can be used for rendering 3D renderings, processing real-world 3D models, creating digital twin villages, or traffic simulations. This is not discussed in detail in the present invention.

[0092] Those skilled in the art will understand that the accompanying drawings are only a schematic diagram of a preferred embodiment, and the serial numbers of the embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0093] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for rapid three-dimensional modeling of mountain settlements based on topographic maps, characterized in that: The method comprises the following steps: Obtaining a topographic map and extracting elevation point data, first building surface data and building annotation data therefrom; Generate an irregular triangulated network and a digital elevation model using the elevation point data; extract basic building elevation information from the digital elevation model and integrate it into the first building surface data to obtain integrated second building surface data; Extracting building height information from the building annotation data and integrating it into the second building surface data to obtain integrated third building surface data; Perform three-dimensional stretching on the third building surface data according to the foundation elevation and building height information to generate a three-dimensional building surface; Converting 3D building surfaces into 3D building models in exchange formats; Import the irregular triangulated network and the building 3D model into the modeling software to generate a 3D settlement model; The basic elevation information of the building is extracted from the digital elevation model and integrated into the first building surface data to obtain the integrated second building surface data: Calculate the center of gravity position of each element in the first building surface data, and generate building center of gravity point data that retains the FID field of the first building surface data; The building center point data is spatially superimposed with the digital elevation model, the elevation value of each element of the building center point data is extracted and saved as the building elevation field, and then the building foundation elevation point data with the first building surface data FID field is generated; Using the first building surface data FID as a connection field, the building elevation field of the building foundation elevation point data is connected to the first building surface data to generate second building surface data containing foundation elevation information; The building height information is extracted from the building annotation data and integrated into the second building surface data to obtain the integrated third building surface data: Converting the building annotation data into points to generate first building annotation point data whose attribute table contains the building annotation information; Modify the attribute table of the first building annotation point data, create a new building layer number field, extract the number representing the building layer number in the building annotation information as the building layer number field value, assign the building layer number field value of the elements whose building annotation information does not contain numbers to 1, and create a new building height field, making it equal to the product of the building layer number field value and the average floor height of the settlement building, to generate the second building annotation point data; Use the Spatial Intersection tool to input the second building annotation point data and the second building surface data to generate the third building annotation point data containing the building height field and the second building surface data FID field; Using the second building surface data FID as the connection field, the building height field of the third building annotation point data is connected to the second building surface data to generate the third building surface data containing the building height information.

2. The method for rapid three-dimensional modeling of mountain settlements based on topographic maps according to claim 1 is characterized in that: The process of obtaining a topographic map and extracting elevation point data, first building surface data, and building annotation data therefrom is as follows: Obtain a large-scale topographic map CAD file covering the target mountain settlement area; Extract the annotation elevation point layer from the topographic map CAD file, save it as an annotation elevation point CAD file, and export the point features as elevation point data in Shapefile format; Extract the residential area and facilities layer from the topographic map CAD file, save it as a residential area and facilities CAD file, export the surface elements as the first building surface data in the Shapefile format, and export the building annotations as building annotation data in the Annotation format.

3. The method for rapid three-dimensional modeling of mountain settlements based on topographic maps according to claim 1 is characterized in that: The method of generating an irregular triangulated network and a digital elevation model using elevation point data is as follows: Use the Create TIN tool to input elevation point data and generate an irregular triangulated network; Use the TIN to Raster tool to input the irregular triangulated network and generate a digital elevation model of the mountain settlement area.

4. The method for rapid three-dimensional modeling of mountain settlements based on topographic maps according to claim 1, characterized in that: The three-dimensional stretching of the third building surface data according to the foundation elevation and building height information to generate the three-dimensional building surface is specifically as follows: According to the base elevation value and building height value of each element, the third building surface data is vertically moved and three-dimensionally stretched so that the bottom elevation of the building is equal to the base elevation value and the vertical height is equal to the building height value, thereby generating a three-dimensional building surface.

5. The method for rapid three-dimensional modeling of mountain settlements based on topographic maps according to claim 1, characterized in that: The conversion of the three-dimensional building surface into the three-dimensional building model in the exchange format is specifically as follows: Use ArcGIS's 3D Layer to Feature Class tool to input the three-dimensional building surface and generate the first building three-dimensional model in the form of a polyhedron; use ArcGIS's Polyhedron to Collada tool to input the first building three-dimensional model and generate the second building three-dimensional model in DAE format.

6. The method for rapid three-dimensional modeling of mountain settlements based on topographic maps according to claim 1, characterized in that: The method of importing the irregular triangulated network and the building 3D model into the modeling software to generate the settlement 3D model is as follows: Select the corresponding modeling software according to the specific application scenario, import the irregular triangulated network and the building 3D model, generate the settlement 3D model, and then use the settlement 3D model to render 3D renderings, process real-life 3D models, build digital twin villages or traffic simulation work scenarios.

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