Two-dimensional and three-dimensional integrated construction method based on DOM and elevation data

Abstract

The invention discloses a two-dimensional and three-dimensional integrated construction method based on DOM and elevation data. The two-dimensional and three-dimensional integrated construction method comprises the following steps: S1, data preparation and processing; s2, collecting vector data; s3, performing projection correction through a correction algorithm; s4, plotting the collected surface feature contour field; and S5, generating an attribute data hitching model, and hitching the variables defined in the rule and the attribute data of the two-dimensional vector so as to realize generation of a rule control model. According to the method, the constraint of a traditional acquisition mode is broken, the problem that two-dimensional and three-dimensional data are different is solved, quick acquisition of two-dimensional vector data is realized, the two-dimensional and three-dimensional precision requirements are met, and important data basis and technical support are provided for live-action three-dimensional Beijing.

Description

Technical Field

[0001] The invention belongs to the technical field of integrated modeling, and specifically is a two- and three-dimensional integrated construction method based on DOM and elevation data. Background Art

[0002] The three-dimensional model is an important spatial resource foundation for digital cities and smart cities. It has the characteristics of strong objectivity and authenticity, and has become a hot spot for current applications. The traditional topographic map house collection process only has two-dimensional information but no three-dimensional information, and it is impossible to build a LOD2 three-dimensional model. Turning the two-dimensional topographic map into three-dimensional is our urgent need and development direction. From collecting two-dimensional to generating a three-dimensional model, it is necessary to meet the plane accuracy of the topographic map and the height accuracy of the house. The previous method was that the topographic map was operated according to the collection method of the topographic map, and the model was built in a monomer modeling way. They were separated from each other, and the graphics were not exactly the same. Therefore, there is an urgent need for a method that can collect two-dimensional vectors while meeting the construction of the LOD2 wireframe white model, that is, a two- and three-dimensional integrated construction method based on DOM and elevation data.

[0003] At present, the methods of topographic map collection mainly include aerial survey stereo collection, point cloud collection, three-dimensional tilt model collection, total station field collection, etc. For areas with rapid urban changes, the above methods are obviously insufficient in production capacity. For example, aerial survey stereo collection is often used in topographic map surveying, which requires technicians to have a high level of aerial survey stereo collection experience and high hardware configuration requirements. The cost of using tilt models to update the corresponding software and hardware investment and the long production cycle of the model will inevitably increase the data production time, and the problem is more prominent for large-scale data collection and update. Summary of the invention

[0004] In view of the above problems, the present invention is proposed to provide a schematic diagram of a two- and three-dimensional integrated construction method based on DOM and elevation data to overcome the above problems or at least partially solve the above problems.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A two-dimensional and three-dimensional integrated construction method based on DOM and elevation data, the method comprising the following steps:

[0007] S1. Data preparation and processing;

[0008] S2, vector data acquisition;

[0009] S3, performing projection correction by using a correction algorithm;

[0010] S4. Draw the contours of the collected features in the field;

[0011] S5. Attribute data connection model generation: connect the variables defined in the rules with the attribute data of the two-dimensional vector to realize rule control model generation.

[0012] Optionally, the data in step S1 includes DOM image data, DSM data or point cloud data, mosaic line data and flight data.

[0013] Optionally, data preparation and processing include coordinate transformation and cropping of existing DOM data and point cloud or DSM data.

[0014] Optionally, the vector data collection in step S2 collects vector data of the contour of the object based on the DOM data, and collects the elevation information of the object based on the OSGB format model generated by the DSM data, or collects the elevation information of the object based on the point cloud data.

[0015] Optionally, performing projection correction by using a correction algorithm in step S3 includes:

[0016] The correction algorithm is used to obtain the accurate correction amount, and the objects with projection errors are translated perpendicular to the direction of the flight path, and the contours and feature points are corrected to obtain the true position of the contours of the objects.

[0017] The original roof is retained, and an association is established between the roof and the corrected ground feature outline, so as to convert between the roof and the outline;

[0018] The roof vector surface provides the vector range for extracting the roof color for subsequent modeling, and uses DOM image data to obtain the roof type.

[0019] Optionally, the collected terrain contours are mapped in the field to investigate the number of floors of the house, the building structure type and the terrain type.

[0020] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0021] 1. The present invention breaks the shackles of traditional acquisition methods, solves the problem of different two-dimensional and three-dimensional data, realizes the rapid acquisition of two-dimensional vector data, and meets the accuracy requirements of two-dimensional and three-dimensional data. The technology is put into the pilot work of the national new basic surveying and mapping in Beijing, and has been widely used in the basic surveying and mapping of Beijing’s land space. It breaks through the results of traditional two-dimensional topographic maps and provides important data foundation and technical support for real three-dimensional Beijing.

[0022] 2. Through the present invention, the traditional two-dimensional topographic map is gradually constructed into a two- and three-dimensional integrated one. The three-dimensional data has the advantages of being real and having a large amount of information, conforming to people's visual habits, and being able to express more spatial relationships. In addition, the data is used to conduct building height change analysis, field of view analysis, sunshine analysis, etc., providing data and technical support for smart cities, digital cities, and digital twin cities. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of a two- and three-dimensional integrated construction method based on DOM and elevation data provided in an embodiment of the present application;

[0024] Figure 2 Collect location diagrams for building elevations;

[0025] Figure 3 Classify the hierarchical graph for texture image resources;

[0026] Figure 4 It is a logic diagram of building rules;

[0027] Figure 5 This is a roof type diagram;

[0028] Figure 6 It is a two-dimensional result map;

[0029] Figure 7 This is the white model result picture;

[0030] Figure 8 The result map of color modeling extraction. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] Embodiment 1:

[0033] See also Figure 1 This embodiment provides a two-dimensional and three-dimensional integrated construction method based on DOM and elevation data, and the method includes the following steps:

[0034] S1. Data preparation and processing. Data preparation and processing include coordinate conversion and cutting of existing DOM data and point cloud or DSM data. If DSM data is used, model generation is required, and OSGB model is generated using DOM and DSM. If point cloud data is used, model generation is not required.

[0035] The data in step S1 include DOM image data, DSM data or point cloud data, mosaic line data and flight data. Quick stitch image data point cloud data can also be used to replace DOM image and DSM data; basic surveying and mapping primitive entity data.

[0036] S2. Vector data collection.

[0037] In step S2, vector data collection collects vector data of the contour of the object based on the DOM data, and collects elevation information of the object based on the OSGB format model generated by the DSM data, or collects elevation information of the object based on the point cloud data.

[0038] S3. Perform projection correction through a correction algorithm.

[0039] The projection correction by the correction algorithm in step S3 includes:

[0040] The correction algorithm is used to obtain the accurate correction amount, and the objects with projection differences are translated perpendicular to the direction of the flight path. The contours and feature points are corrected to obtain the true position of the contours of the objects.

[0041] The original roof is retained and an association is established between the roof and the corrected terrain contour for conversion between the roof and the contour.

[0042] The roof vector surface provides the vector range for extracting the roof color for subsequent modeling, and uses DOM image data to obtain the roof type. The roof types are divided into eight categories: "flat roof, flat roof (with parapet), single slope roof, pyramid roof, double slope roof, four-slope roof, dome roof, arched roof".

[0043] S4. Draw the collected contours of the terrain in the field to investigate the number of floors, building structure type and terrain type of the house. After the indoor work is sorted out, batch assign the elevation values ​​of the house nodes and output the designated modeled terrain in batches with one click.

[0044] S5, attribute data hook model generation, hook the variables defined in the rules and the attribute data of the two-dimensional vector to achieve rule-controlled model generation. For house modeling, it is necessary to establish an association between the building's splash height, eaves height, highest elevation, roof type, number of floors above ground and rule variables, and build a three-dimensional model according to the house attributes.

[0045] This embodiment breaks the constraints of traditional collection methods, solves the problem of different two-dimensional and three-dimensional data, realizes the rapid collection of two-dimensional vector data, meets the accuracy requirements of two-dimensional and three-dimensional, and puts this technology into the national new basic surveying and mapping Beijing pilot work. It has been widely used in the basic surveying and mapping of Beijing’s land space, breaking through the traditional two-dimensional topographic map results form, and providing an important data foundation and technical support for real-life three-dimensional Beijing.

[0046] Through this embodiment, the traditional two-dimensional topographic map is gradually constructed into a two- and three-dimensional integrated one. The three-dimensional data has the advantages of being real and having a large amount of information, conforming to people's visual habits, and being able to express more spatial relationships. In addition, the data is used to conduct building height change analysis, field of view analysis, sunshine analysis, etc., providing data and technical support for smart cities, digital cities, and digital twin cities.

[0047] Embodiment 2:

[0048] 1. Data preparation

[0049] The data that need to be prepared include DOM image data, DSM data or point cloud data, mosaic line data, and aerial flight data; quick-joined image data and point cloud data can also be used to replace DOM images and DSM data; basic surveying and mapping primitive entity data.

[0050] 2. Vector information collection and correction

[0051] DOM image data and DSM data or point cloud data are used to collect the plan position of the house and assign information such as house elevation, roof type, and house building structure type.

[0052] By selecting the feature, input the flight strip information where the feature is located, and calculate the projection correction value. The correction value is calculated by collecting the house height and the flight strip and route centerline data, and the vector spot of the correct position is generated. The original roof vector surface is retained, and the roof color information is subsequently extracted using the roof vector.

[0053] The number of floors and building structure type of the house are investigated and verified in the field, and the information is stored in the designated fields in the office.

[0054] 3. Generate LOD2 model

[0055] Modeling data preparation:

[0056] The modeling base map data consists of terrain data and vector data. The terrain elevation file attached with the terrain image can be used as terrain data. The data source of the vector data is 1:500 and 1:2000 basic geographic information element data. After the basic geographic information element data is converted to produce two-dimensional geographic entity data, the attribute information of the entity data is collected. The specific number and type of attribute fields are determined by the results that need to be presented in the modeling. For example, for a modeling project whose main goal is to present the real bottom height, building height, roof structure and number of floors of a house, the attribute fields collected are shown in Table 1.

[0057] Table 1 Attribute parameters of house rules collected in the early stage

[0058]

[0059] Among them, converting the two-dimensional vector into a three-dimensional vector as the driving object of the CGA rule and constructing a house model with real height requires collecting the building's splash water elevation, eaves elevation, and highest point elevation. Figure 2 shown.

[0060] Texture library preparation:

[0061] Typical textures of house facades and roofs are collected by tilting models or taking photos on site. After being cropped and adjusted by image processing software such as Photoshop, they are classified and stored in corresponding projects.

[0062] Under the file directory, the directory hierarchy is as follows Figure 3 , and named after the category:

[0063] (facades_groundfloors_01

[0064] roofs_sloped_01

[0065] roof_sloped_02……).

[0066] CGA Rules Writing:

[0067] CGA rules complete repetitive work by writing codes to achieve the purpose of batch automatic modeling. The principle of rule-based modeling is to describe and constrain the common characteristics of objects in a regular manner, determine how the model is generated through these constraints, and keep it associated with the geometric shape with a parameter (variable). By adjusting the parameter value, the change of the model's geometric shape characteristics can be controlled.

[0068] For the definition of house modeling rules, first define the variable (attr) to prepare for calling the parameters in the attribute table. Function operations can be added when defining the variable. Then stretch (extrude) the two-dimensional house surface element into a three-dimensional block. The stretching height is calculated based on the building eaves elevation and the ground elevation. Secondly, separate the obtained three-dimensional block (comp) and divide the facade and top surface to facilitate the subsequent definition of rules for different surfaces; finally, construct the roof structure for the separated top surface according to the "roof type" attribute of the element, and divide the facade vertically and then horizontally according to the "number of floors above ground" attribute of the element to obtain the schematic structure of floors and windows, so as to obtain a more detailed house model, such as Figure 4 The built-in roof function can generate roof types such as Figure 5 shown.

[0069] Roof color value extraction:

[0070] The color value is extracted using the roof range data before vector correction and the DOM image data used in that year. The RGB value is extracted using the Python language and written to the specified attribute field.

[0071] Model output:

[0072] Define various rules for the common characteristics of buildings, and create detailed models through iterative refinement of designs, such as coloring of building roofs, establishment of eaves and roof structures, and segmentation of doors and windows. Use different defined rules for different building characteristics, and the differences in details can be controlled by the parameters of associated attributes. Generate a 3D model based on the rules and attribute parameters according to the parametric modeling process, and export it to various 3D data formats such as obj and gdb as needed.

[0073] In order to verify the effectiveness of this method, some areas were selected for experiments in the early stage. The test area is about 80 square kilometers. Four 1:2000 images were randomly selected for accuracy testing to meet the accuracy requirements of 1:2000 images. Subsequently, it was widely used in the production of basic spatial surveying and mapping of Beijing.

[0074] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A two-dimensional and three-dimensional integrated construction method based on DOM and elevation data, characterized in that: The method comprises the following steps: S1. Data preparation and processing; S2, vector data acquisition; S3, performing projection correction by using a correction algorithm; S4. Draw the contours of the collected features in the field; S5. Attribute data connection model generation: connect the variables defined in the rules with the attribute data of the two-dimensional vector to realize rule control model generation.

2. A two-dimensional and three-dimensional integrated construction method based on DOM and elevation data as claimed in claim 1, characterized in that: The data in step S1 include DOM image data, DSM data or point cloud data, mosaic line data and flight data.

3. A two-dimensional and three-dimensional integrated construction method based on DOM and elevation data as claimed in claim 1, characterized in that: Data preparation and processing include coordinate transformation and cropping of existing DOM data and point cloud or DSM data.

4. A two-dimensional and three-dimensional integrated construction method based on DOM and elevation data as claimed in claim 1, characterized in that: In step S2, vector data collection collects vector data of the contour of the object based on the DOM data, and collects elevation information of the object based on the OSGB format model generated by the DSM data, or collects elevation information of the object based on the point cloud data.

5. A two-dimensional and three-dimensional integrated construction method based on DOM and elevation data as claimed in claim 1, characterized in that: The projection correction by the correction algorithm in step S3 includes: The correction algorithm is used to obtain the accurate correction amount, and the objects with projection errors are translated perpendicular to the direction of the flight path, and the contours and feature points are corrected to obtain the true position of the contours of the objects. The original roof is retained, and an association is established between the roof and the corrected ground feature outline, so as to convert between the roof and the outline; The roof vector surface provides the vector range for extracting the roof color for subsequent modeling, and uses DOM image data to obtain the roof type.

6. A two-dimensional and three-dimensional integrated construction method based on DOM and elevation data as claimed in claim 1, characterized in that: The collected terrain contours are mapped in the field to investigate the number of floors of the house, the type of building structure and the type of terrain.

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