Mountain settlement rapid three-dimensional modeling method based on topographic map

Abstract

The invention discloses a quick three-dimensional modeling method for mountain settlement based on a topographic map. The method comprises the following steps: acquiring the topographic map, and respectively extracting elevation point data, first building surface data and building annotation data from the topographic map; generating a triangulated irregular network and a digital elevation model by utilizing the elevation point data; extracting basic elevation information of the building from the digital elevation model and integrating the basic elevation information into the first building surface data to obtain integrated second building surface data; extracting building height information from the building annotation data and integrating the building height information into the second building surface data to obtain integrated third building surface data; performing 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 the three-dimensional building surface into a building three-dimensional model in an exchange format; and importing the triangulated irregular network and the building three-dimensional model into modeling software to generate a settlement three-dimensional model. According to the method, the terrain elevation, the building graph and the building height information in the topographic map can be integrated, and rapid and refined three-dimensional modeling of mountain settlement is realized through parameterized three-dimensional stretching.

Description

Technical Field

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

[0002] The three-dimensional model of the settlement 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 mountain settlement modeling: if three-dimensional modeling software is used, the workload is large and the time is long; 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] The present invention provides a method for rapid 3D modeling of mountain settlements based on topographic maps. The present invention can integrate terrain elevation, building graphics and building height information in topographic maps, and then realize rapid and refined 3D modeling of mountain settlements through parametric 3D stretching, as described below:

[0006] A method for rapid three-dimensional modeling of mountain settlements based on topographic maps, 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 respectively;

[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] Convert 3D building surfaces into 3D building models in exchange format;

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

[0014] The method of obtaining a topographic map and extracting elevation point data, first building surface data and building annotation data respectively 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 in it as elevation point data in Shapefile format;

[0017] The residential area and facility layers are extracted from the topographic map CAD file and saved as residential area and facility CAD files. The surface elements therein are exported as the first building surface data in the Shapefile format, and the building annotations therein are exported 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 specifically 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 range.

[0021] The extraction of the basic elevation information of the building 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 centroid position of each element in the first building surface data, and generate building centroid point data retaining the FID field of the first building surface data;

[0023] The building gravity point data is spatially superimposed with the digital elevation model, the elevation value of each element of the building gravity point data is extracted and saved as a building elevation field, and then the building foundation elevation point data retaining 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 basic elevation point data is connected to the first building surface data to generate second building surface data containing basic elevation information.

[0025] The extraction of building height information from the building annotation data and integration into the second building surface data to obtain the integrated third building surface data is specifically:

[0026] Convert the building annotation data into points, and generate first building annotation point data whose attribute table contains 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 number of building layers in the building annotation information as the building layer number field value, and assign the building layer number field value of the element that does not contain a number in the building annotation information to 1, create a new building height field, and make it equal to the product of the building layer number field value and the general floor height of the settlement building, and 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 including 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 method of converting 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 3D building surface and generate a first building 3D model in the form of a polyhedron; use ArcGIS's polyhedron to Collada tool to input the first building 3D model and generate a second building 3D model in DAE format.

[0034] The step of importing the irregular triangulated network and the three-dimensional building model into the modeling software to generate the three-dimensional settlement 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 to render 3D renderings, process real-life 3D models, build 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. The present invention integrates terrain elevation and building height information in topographic maps, quickly generates surface terrain and batch stretches building elements in a parametric manner, and 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, which 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 rapid 3D modeling method for 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] 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 only to provide a better understanding of the 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: if three-dimensional modeling software is used, the workload is large and the time is long; if three-dimensional measurement technology is used, the accuracy is often low and the results are difficult to further fine-tune.

[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] In order to facilitate understanding of the present application, the following terms are explained in the embodiments of the present invention:

[0045] A topographic map is a map that is surveyed and mapped by professional institutions in accordance with national and local standards and managed and provided by the natural resources department. The embodiment of the present invention requires the use of large-scale topographic maps such as 1:500, 1:1000 or 1:2000. According to the national standard for the classification of basic geographic elements, a topographic map must contain two types of elements: "residential areas and facilities" and "elevation annotation points". The former covers all buildings and their annotation information, and the latter covers all elevation points. In a vector topographic map, the two types of elements are stored in one or more layers respectively.

[0046] Elevation point is 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 are text annotations that mark the building structure type and number of floors. They are composed of text and numbers. According to national and local standards, large-scale topographic maps should mark the building structure and number of floors one by one, and the location should be above the corresponding building. The annotation of a one-story building 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 an ordered array of numerical values. It is a branch of the 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 ground or other irregular surfaces. It is superior in representing complex surfaces and is widely used in digital mapping, map surface modeling, and other work.

[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 A rapid three-dimensional modeling method for mountain settlements based on topographic maps is provided in an embodiment of the present invention. Figure 1 As shown, the method for rapid three-dimensional modeling of mountain settlements based on topographic maps provided in 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 therefrom 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: performing 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 introduced below.

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

[0063] Wherein, step S1 comprises:

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

[0065] S12: extract the annotation elevation point layer from the topographic map CAD file and save it as the 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 elements of 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 the 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 above-mentioned residential area and facility CAD file layer group into the above-mentioned file geodatabase, and generate building annotation data in Annotation format.

[0068] Wherein, step S2 comprises:

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

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

[0071] Wherein, step S3 comprises:

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

[0073] The building gravity 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 gravity point data is located at the gravity center position of the corresponding element in the first building surface data.

[0074] S32: Use the “Extract Values ​​to Points” tool of ArcGIS to generate building foundation elevation point data using the building centroid point data as input point feature 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 of each building surface element.

[0076] S33: Use the "Join Field" tool of 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", generate the second building surface data, and change the name of the field "RASTERVALU" to "Foundation Elevation" in ArcCatalog.

[0077] Wherein, step S4 comprises:

[0078] S41: In the aforementioned Arcmap document, using the “Feature To Point” tool of ArcGIS, input the building annotation data to generate the 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 1 floor for the building.

[0080] S42: export the attribute table of the first building annotation point data, convert it to ANSI code, save it as a CSV file and open it with EXCEL, create new "building floors" and "building height" columns; use regular expressions to extract the value of the "Text" column of each row as the "building floors" cell value of the same row, if the "Text" column content of a row does not have a number, assign the "building floors" cell value of the row to 1; calculate the "building height" cell value to make it equal to the product of the "building floors" cell value of the same row and the general floor height of the settlement building (for example: 3 meters), and save it as an XLS file after the modification is completed; use ArcGIS's "Table To Table" tool, 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, so as to modify the annotation point data attribute table and generate 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 field of the second building surface data is retained using the "FID_Second Building Surface" field.

[0084] S44: Use the "Join Field" tool of ArcGIS, use 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" as the stretching method, and generating a three-dimensional building surface after application.

[0087] Wherein, step S6 comprises:

[0088] S61: In the aforementioned ArcScene document, using the “Layer 3D to Feature Class” tool of ArcGIS, input the three-dimensional building surface to generate a first three-dimensional 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] Wherein, 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 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. The results of three-dimensional modeling can be imported into traditional modeling software for further adjustment and application. For example, the settlement three-dimensional model is used in work scenarios such as rendering three-dimensional renderings, processing real-life three-dimensional models, making digital twin villages or traffic simulations, which will not be elaborated in the embodiment of the present invention.

[0092] Those skilled in the art will appreciate that the accompanying drawing is 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 principle of the present invention should be included in the protection scope 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 respectively; Generate an irregular triangulated network and a digital elevation model using the elevation point data; extract basic elevation information of the building 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; Convert 3D building surfaces into 3D building models in exchange format; Import the irregular triangulated network and the building 3D model into the modeling software to generate a 3D model of the settlement.

2. 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 obtaining a topographic map and extracting elevation point data, first building surface data and building annotation data therefrom is specifically 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 in it as elevation point data in Shapefile format; The residential area and facility layers are extracted from the topographic map CAD file and saved as residential area and facility CAD files. The surface elements therein are exported as the first building surface data in the Shapefile format, and the building annotations therein are exported 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 specifically 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 range.

4. The method for rapid three-dimensional modeling of mountain settlements based on topographic maps according to claim 1 is characterized in that: 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, specifically: Calculate the centroid position of each element in the first building surface data, and generate building centroid point data retaining the FID field of the first building surface data; The building gravity point data is spatially superimposed with the digital elevation model, the elevation value of each element of the building gravity point data is extracted and saved as a building elevation field, and then the building foundation elevation point data retaining the first building surface data FID field is generated; Using the first building surface data FID as the connection field, the building elevation field of the building basic elevation point data is connected to the first building surface data to generate second building surface data containing basic elevation information.

5. The method for rapid three-dimensional modeling of mountain settlements based on topographic maps according to claim 1 is characterized in that: 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, which is specifically: Convert the building annotation data into points, and generate first building annotation point data whose attribute table contains 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 number of building layers in the building annotation information as the building layer number field value, and assign the building layer number field value of the element that does not contain a number in the building annotation information to 1, create a new building height field, and make it equal to the product of the building layer number field value and the general floor height of the settlement building, and 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 including 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.

6. The method for rapid three-dimensional modeling of mountain settlements based on topographic maps according to claim 1 is 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.

7. 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 converting 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 3D building surface and generate a first building 3D model in the form of a polyhedron; use ArcGIS's polyhedron to Collada tool to input the first building 3D model and generate a second building 3D model in DAE format.

8. 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 importing the irregular triangulated network and the building three-dimensional model into the modeling software to generate the settlement three-dimensional model is specifically 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 and other work scenarios.

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