Design method and system for terrain fitting and elevation interpolation along rail transit line

Abstract

The invention discloses a design method and system for terrain fitting and elevation interpolation along a rail transit line. The method comprises the following steps: screening and extracting topographic map elevation data; constructing and generating an improved triangulation network model for fitting the terrain; interpolating line mileage points pile by pile by using a functional component of the triangulation network model; in the working process of rail transit line selection design, data of pile-by-pile ground elevation along a line can be efficiently and accurately obtained, by taking query of N elevation points on a topographic map and M mileage points on the line as an example, the calculation amount required for constructing a triangulation network is reduced to N. (square root of N). 3 / 2 times at most, the calculation amount required for interpolating the elevation is reduced to square root of N + M times, and the calculation amount required for constructing the triangulation network is reduced to N. Compared with other methods and systems at the present stage, the method and system provided by the invention have the advantages that the calculated amount of model creation and batch interpolation is reduced in index level, and the working precision and efficiency of terrain fitting and pile-by-pile elevation interpolation in the rail transit line selection design are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of rail transit line selection, and in particular to a design method and system for terrain fitting and elevation interpolation along a rail transit line. Background Art

[0002] With the acceleration of urbanization, the planning and construction of intercity and urban rail transit has become one of the important tasks of major urban agglomerations and metropolitan areas. Line selection and design is a key link in the planning and construction of rail transit. Its main task is to complete the plane alignment and longitudinal slope determination of the line on the topographic map. After the plane alignment is completed, it is necessary to obtain the ground elevation data of each pile along the line according to the topographic map to reflect the undulating terrain along the line, and complete the slope design of the longitudinal section in combination with the control elements along the line. With the continuous expansion of the urban framework, the length of rail transit lines continues to increase, and the intervals between ground elevation points are gradually encrypted to the meter level, which puts higher requirements on the acquisition of elevation data.

[0003] At present, there are several main methods and systems for obtaining the ground elevation of each pile of the line: manual method, nearest point method, three-point interpolation method and triangulation interpolation method. The manual method relies on manual judgment of the ground undulation along the line and records the elevation of key mileage points, but this method is greatly affected by human factors and has low data acquisition efficiency. The nearest point method uses a computer to find the nearest elevation point in the topographic map and assign a value. Although the efficiency is improved, the accuracy is low. The three-point interpolation method interpolates the plane fitting of the three nearest elevation points, which improves the accuracy compared to the nearest point method, but there is still a large deviation. The triangulation interpolation method uses the Delaunay triangulation to fit the terrain and obtains the elevation through triangular patch interpolation. It has high accuracy and stability, but the calculation is large and the efficiency needs to be improved.

[0004] Although the existing technology has solved the problem of obtaining elevation data to a certain extent, there are still many shortcomings. The manual method and the nearest point method have low accuracy and cannot meet the high-precision requirements of modern rail transit line selection and design. Although the three-point interpolation method has improved in accuracy, there are still large deviations. Although the triangulation interpolation method has high accuracy, it has a large amount of calculation, especially when processing large-scale elevation point data, the efficiency is low. Therefore, there is an urgent need for an improved method and system for terrain fitting and pile-by-pile elevation interpolation, which can not only ensure high accuracy, but also greatly improve the efficiency of data processing to meet the high requirements of rail transit line selection and design. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the purpose of the present invention is to provide a design method and system for terrain fitting and elevation interpolation along a rail transit line. The method and system construct and generate an improved triangulated network model for fitting the terrain by screening and extracting elevation data of a topographic map, and use the functional components of the triangulated network model to interpolate the line mileage points one by one. In the process of rail transit line selection and design, the data of ground elevation of each pile along the line can be obtained efficiently and accurately. Taking N elevation points on a topographic map and M mileage points on the line as an example, the amount of calculation required for constructing a triangulated network is reduced to at most N·(√N)·3 / 2 times, and the amount of calculation required for interpolating the elevation is reduced to at most √N+M times. Compared with other methods and systems at this stage, the method and system provided by the present invention have an exponential reduction in the amount of calculation for creating a model and batch interpolation, which greatly improves the working accuracy and efficiency of terrain fitting and pile-by-pile elevation interpolation in rail transit line selection and design.

[0006] According to a first aspect of the present invention, a design method for terrain fitting and elevation interpolation along a rail transit line is provided, comprising:

[0007] S100, importing a topographic map file, extracting elevation point data therein, and forming an original elevation point set;

[0008] S200, filtering the original elevation point set, excluding points whose positions are out of range or whose elevations are out of standard according to coordinate and elevation data, and obtaining a filtered elevation point set;

[0009] S300, importing the filtered elevation point set into the improved triangulated network model, initializing the vertex object set, forming a plane rectangular boundary that can envelop all elevation points, inserting the first elevation point into the plane rectangular boundary, dividing to form an initial improved triangulated network model consisting of four boundary triangles, and initializing the triangle surface object set and edge line object set in the model;

[0010] S400, sequentially inserting the remaining elevation points into the initial improved triangulated network model, successively triangulating the local network where the insertion points are located, and improving the corresponding point, edge, and surface object sets to obtain an improved triangulated network model for fitting the terrain;

[0011] S500: Based on the improved triangulated network model for fitting terrain, query and perform elevation interpolation calculation on each mileage point on the line plane to obtain elevation data of all mileage points.

[0012] Furthermore, the improved triangulated network model includes three functional component modules: an initial creation module, a positioning query module and a model I / O module.

[0013] Furthermore, the improved triangulated network model includes three linked list data sets: a vertex object set, an edge object set and a triangle surface object set.

[0014] Furthermore, the vertex object set, edge line object set and triangle surface object set correspond to three subsidiary object models, namely, a vertex object model, an edge line object model and a triangle surface object model.

[0015] Furthermore, the vertex object model is a data carrier of elevation points, and mainly stores the spatial coordinates and other attribute information of terrain elevation points.

[0016] Furthermore, the edge object model does not store entity data, but only stores relationship information and interface modules, including four functional component modules: endpoint relationship management module, two-side triangle relationship management module, spatial relationship determination module and information interpolation calculation module.

[0017] Furthermore, the triangular face image model does not store entity data, but only stores relationship information and an interface module, including four functional component modules: a vertex relationship management module, an edge relationship management module, a spatial relationship determination module, and a triangular interpolation calculation module.

[0018] Furthermore, the step S400 of inserting the remaining elevation points into the initial triangulated mesh model to obtain an improved triangulated mesh model for fitting the terrain includes: locating the triangle where the insertion point is located through the positioning query module, and then finding all adjacent triangles around the triangle that do not meet the circumscribed circle criterion through recursive calls of the edge-face relationship, erasing the triangle and the adjacent triangles that do not meet the requirements and their adjacent edges from the triangle surface object set and the edge line object set to form a local hole, and then triangulating the hole using the insertion point, adding the newly generated triangles and edges to the triangle surface object set and the edge line object set until all elevation points are inserted, and finally removing the triangle containing the working boundary vertices to obtain an improved triangulated mesh model for fitting the terrain.

[0019] Further, step S500 includes:

[0020] S501, querying each mileage point through the positioning query module, first finding the boundary triangle closest to the first mileage point according to the working boundary, and determining whether the first mileage point is inside the boundary triangle;

[0021] S502: when the first mileage point is not inside the boundary triangle, first determine the orientation relationship between the first mileage point and the boundary triangle, then search for adjacent triangles in the same direction through the point-edge-face relationship of the boundary triangle, set the adjacent triangle as the current triangle, and then search cyclically on this basis until the triangle where the first mileage point is located is found, and call the interpolation calculation module to obtain the elevation data of the first mileage point; when the first mileage point is inside the boundary triangle, directly call the interpolation calculation module to obtain the elevation data of the first mileage point;

[0022] S503, continue to query the next mileage point. The positioning triangle of the next mileage point does not need to start from the working boundary. It only needs to start searching from the positioning triangle of the previous mileage point until the query of each mileage point is completed and the elevation interpolation calculation is completed.

[0023] According to a second aspect of the present invention, a design system for terrain fitting and elevation interpolation along a rail transit line is provided, comprising:

[0024] The first module is used to import a topographic map file, extract the elevation point data therein, and form an original elevation point set;

[0025] The second module is used to perform data screening on the original elevation point set, exclude points whose positions are out of range or whose elevations exceed the standard according to the coordinate and elevation data, and obtain a screened elevation point set;

[0026] The third module is used to import the filtered elevation point set into the improved triangulated network model, initialize the vertex object set, form a plane rectangular boundary that can envelop all elevation points, insert the first elevation point into the plane rectangular boundary, divide and form an initial improved triangulated network model consisting of four boundary triangles, and initialize the triangle surface object set and edge line object set in the model;

[0027] The fourth module is used to sequentially insert the remaining elevation points into the initial improved triangulated network model, successively triangulate the local network where the insertion points are located, and improve the corresponding point, edge, and surface object sets to obtain an improved triangulated network model for fitting the terrain;

[0028] The fifth module is used to query and perform elevation interpolation calculation on each mileage point on the line plane based on the improved triangulated network model for fitting the terrain, so as to obtain the elevation data of all mileage points.

[0029] Beneficial effects of the present invention:

[0030] 1. The method and system construct and generate an improved triangulated network model for fitting terrain by screening and extracting elevation data from topographic maps, and use the functional components of the triangulated network model to interpolate line mileage points one by one. In the process of rail transit line selection and design, the data of ground elevation of each pile along the line can be obtained efficiently and accurately. Taking N elevation points on the topographic map and M mileage points on the line as an example, the amount of calculation required for constructing the triangulated network is reduced to at most N·(√N)·3 / 2 times, and the amount of calculation required for interpolating the elevation is reduced to √N+M times. Compared with other methods and systems at this stage, the method and system provided by the present invention have an exponential reduction in the amount of calculation for creating models and batch interpolation, which greatly improves the accuracy and efficiency of terrain fitting and pile-by-pile elevation interpolation in rail transit line selection and design.

[0031] 2. The improved triangulated network model constructed by this method conforms to the basic geometric characteristics of the Delaunay triangulated network. According to the needs of line cutting terrain, the model design of the triangulated network and its affiliated objects is optimized in a targeted manner, which reduces the memory space occupied by data, expands the relevance of its relational data through pointers, and improves the relationship management, search and query capabilities of the overall network.

[0032] 3. The system can store the vertex object set, edge object set, triangle surface object set and their corresponding relationship models of the instantiated triangulated network model as TTN custom format files through the I / O module, and supports importing TTN files into the model to re-instantiate the triangulated network model.

[0033] Additional aspects and advantages of the present application will be partially given in the following description, which will become apparent from the following description, or will be understood through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0035] Figure 1 is a flow chart of a design method for terrain fitting and elevation interpolation along a rail transit line in an embodiment of the present invention;

[0036] Figure 2 It is a schematic diagram of the model relationship of an improved triangulated network model and its subordinate objects in a design method for terrain fitting and elevation interpolation along a rail transit line according to an embodiment of the present invention;

[0037] Figure 3 It is a specific flow chart of steps S300 and S400 in a design method for terrain fitting and elevation interpolation along a rail transit line according to an embodiment of the present invention;

[0038] Figure 4It is a specific flow chart of step S500 in a design method for terrain fitting and elevation interpolation along a rail transit line according to an embodiment of the present invention;

[0039] Figure 5 It is a schematic diagram of an example of a positioning search path in a process of querying mileage points through a positioning query module in a design method for terrain fitting and elevation interpolation along a rail transit line in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0041] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present application refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0042] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless specifically defined as in the embodiments of this application.

[0043] The present invention provides a design method and system for terrain fitting and elevation interpolation along a rail transit line. The method and system construct and generate an improved triangulated network model for fitting terrain by screening and extracting elevation data of a topographic map, and interpolate line mileage points one by one using functional components of the triangulated network model. In the process of rail transit line selection and design, the data of ground elevation of each pile along the line can be efficiently and accurately obtained. Taking N elevation points on a topographic map and M mileage points on a line as an example, the amount of calculation required for constructing a triangulated network is reduced to at most N·(√N)·3 / 2 times, and the amount of calculation required for interpolating elevation is reduced to √N+M times. Compared with other methods and systems at the current stage, the method and system provided by the present invention have an exponential reduction in the amount of calculation for creating a model and batch interpolation, which greatly improves the working accuracy and efficiency of terrain fitting and pile-by-pile elevation interpolation in rail transit line selection and design.

[0044] Embodiment 1:

[0045] like Figure 1 As shown, an embodiment of the present invention provides a design method for terrain fitting and elevation interpolation along a rail transit line, including:

[0046] S100, importing a topographic map file, extracting elevation point data therein, and forming an original elevation point set;

[0047] S200, filtering the original elevation point set, excluding points whose positions are out of range or whose elevations are out of standard according to coordinate and elevation data, and obtaining a filtered elevation point set;

[0048] S300, importing the filtered elevation point set into the improved triangulated network model, initializing the vertex object set, forming a plane rectangular boundary that can envelop all elevation points, inserting the first elevation point into the plane rectangular boundary, dividing to form an initial improved triangulated network model consisting of four boundary triangles, and initializing the triangle surface object set and edge line object set in the model;

[0049] S400, sequentially inserting the remaining elevation points into the initial improved triangulated network model, successively triangulating the local network where the insertion points are located, and improving the corresponding point, edge, and surface object sets to obtain an improved triangulated network model for fitting the terrain;

[0050] S500: Based on the improved triangulated network model for fitting terrain, query and perform elevation interpolation calculation on each mileage point on the line plane to obtain elevation data of all mileage points.

[0051] The improved triangulated network model complies with the basic geometric characteristics of the Delaunay triangulated network. Aiming at the needs of line cutting terrain, the model design of the triangulated network and its affiliated objects is optimized, which reduces the memory space occupied by data, expands the relevance of its relational data through pointers, and improves the relationship management, search and query capabilities of the overall network.

[0052] like Figure 2As shown, the improved triangulated network model includes three functional component modules, namely, the initial creation module, the positioning query module and the model I / O module, and three linked list data sets, namely, the vertex object set, the edge object set and the triangle surface object set. The function of the initial creation module is to construct the entire triangulated network model entity based on the externally imported elevation point data, and to instantiate the vertex object set, the edge object set and the triangle surface object set of the model. The model I / O module supports the instantiated triangulated network model to store the vertex object set, the edge object set, the triangle surface object set and their corresponding relationship models as TTN custom format files, and also supports importing TTN files into the model to re-instantiate the triangulated network model; the positioning query module is applied in both the step of generating the improved triangulated network model in S400 and the step of interpolating the line mileage points one by one in S500.

[0053] Furthermore, the vertex object set, edge object set and triangle object set correspond to three subsidiary object models, namely, vertex object model, edge object model and triangle object model. The vertex object model is the data carrier of the elevation point, and mainly stores the spatial coordinates and other information of the terrain elevation point; the edge object model does not store entity data, and the relationship between its pointer and the vertex object set is controlled by the endpoint relationship management module, and the relationship between its pointer and the triangle object set is controlled by the triangle relationship management modules on both sides. Through these two relationship modules, the edge object does not need to store spatial geometric data, and can determine the geometric features and spatial relationships of the edge through the vertex relationship at both ends and the triangle relationship on both sides; the triangle object model does not store entity data, and the relationship between its pointer and the vertex object set is controlled by the vertex relationship management module, and the relationship between its pointer and the edge object set is controlled by the edge relationship management module. Through these two relationship modules, the triangle object does not need to store spatial geometric data, and can determine the geometric features and spatial relationships of the triangle through the three vertex relationships and the three edge relationships.

[0054] like Figure 3As shown, the specific steps of steps S300 and S400 include: initializing the vertex object set of the improved triangulated network model according to the valid elevation point set, and forming a rectangular working boundary that envelops all points; inserting the first point based on the rectangular boundary, dividing the rectangular working boundary, and forming an initial triangulated network composed of four triangles; setting the point-edge-face relationship of the newly generated triangles and edges, and adding them to the triangle face object set and the edge line object set; and then inserting the remaining elevation points into the initial triangulated network in turn; during the insertion process, it is necessary to first use the positioning query module to locate the triangle where the insertion point is located; after finding the triangle, the edge-face relationship is used to locate the triangle. Recursive calls are made to find all adjacent triangles around the triangle that do not meet the circumscribed circle criterion. The circumscribed circle criterion means that the insertion point should not be located in the circumscribed circle of adjacent triangles. The triangles and adjacent triangles that do not meet the requirements, as well as their adjacent edges, are erased from the triangle surface object set and the edge line object set to form local holes. The holes are then triangulated using the insertion points. After the point-edge-face relationship of the newly generated triangles and edges is set, they are added to the triangle surface object set and the edge line object set until all vertices are inserted. Finally, the triangles containing the working boundary vertices are removed to obtain the triangulated network model for fitting the terrain.

[0055] like Figure 4 As shown, the specific steps of step S500 include: when the program traverses the mileage points one by one for positioning query, it will call the positioning query module of the triangulation model component. If it is the first mileage point query, the module will find the boundary triangle closest to the point through the working boundary, and enter a loop search based on the triangle. First, it is determined whether it is inside the triangle. If not, the orientation relationship between the point and the triangle is determined, and then the adjacent triangle with the same direction as the point is found through the point-edge-face relationship of the triangle. The adjacent triangle is set as the current triangle, and the loop search is continued based on it until the triangle located by the first mileage point is found, and the interpolation calculation module of the triangle is called to obtain the elevation of the mileage point as the return value of the module. After the assignment is completed, the program continues to query the module for the next point. The positioning triangle of the next point does not need to start from the boundary, but only needs to start searching from the positioning triangle of the previous mileage point until the query is completed for each mileage point. After all the elevations of the mileage points are obtained, it can support output as a DMX custom format file.

[0056] like Figure 5As shown, the black triangulated network in the figure is a triangulated network containing a rectangular working boundary. The outermost rectangle is the rectangular working boundary, which contains four corner points. After removing the triangle containing the four corner points, the remaining part is a triangulated network object constructed by "valid" elevation points. In the middle of the triangulated network, there is a row of line mileage points that are arranged from left to right in sequence, one by one, and in sequence. They are red dots in the figure. To query a mileage point on the left, it is necessary to find the boundary triangle closest to the query point from the rectangular working boundary, and find the adjacent triangles in the same direction as the point through the point-edge-face relationship of the triangle, and continuously approach the triangle located by the query point. After finding the positioning triangle of the first point, the subsequent mileage points can use the positioning triangle of the previous point as the starting triangle to search for their own positioning triangles until they reach the last mileage point. The blue trajectory line in the figure is the search trajectory of the triangle. In summary, the present invention has innovatively designed the triangulated network and its affiliated object models through this logical idea, and provided this improved or innovative method and system for terrain fitting and pile-by-pile elevation interpolation, so as to efficiently and accurately obtain the data of pile-by-pile ground elevation along the line, thereby improving the overall efficiency of rail transit line selection and design work. Taking N elevation points on the topographic map and M mileage points on the line as an example, the amount of calculation required to construct the triangulated network is reduced to at most N·(√N)·3 / 2 times, and the amount of calculation required for interpolating the elevation is reduced to √N+M times. Compared with other methods and systems at this stage, the method and system provided by the present invention have an exponential reduction in the amount of calculation for creating models and batch interpolation, which greatly improves the working accuracy and efficiency of terrain fitting and pile-by-pile elevation interpolation in rail transit line selection and design.

[0057] Embodiment 2:

[0058] The embodiment of the present invention provides a design system for terrain fitting and elevation interpolation along a rail transit line, comprising:

[0059] The first module is used to import the topographic map file, extract the elevation point data therein, and form an original elevation point set;

[0060] The second module is used to perform data screening on the original elevation point set, exclude points whose positions are out of range or whose elevations exceed the standard according to the coordinate and elevation data, and obtain a screened elevation point set;

[0061] The third module is used to import the filtered elevation point set into the improved triangulated network model, initialize the vertex object set, form a plane rectangular boundary that can envelop all elevation points, insert the first elevation point into the plane rectangular boundary, divide and form an initial improved triangulated network model consisting of four boundary triangles, and initialize the triangle surface object set and edge line object set in the model;

[0062] The fourth module is used to sequentially insert the remaining elevation points into the initial improved triangulated network model, successively triangulate the local network where the insertion points are located, and improve the corresponding point, edge, and surface object sets to obtain an improved triangulated network model for fitting the terrain;

[0063] The fifth module is used to query and perform elevation interpolation calculation on each mileage point on the line plane based on the improved triangulated network model for fitting the terrain, so as to obtain the elevation data of all mileage points.

[0064] It should be understood that, although the steps in the flowchart of the accompanying drawings are displayed in sequence as indicated by the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least a part of the steps in the flowchart of the accompanying drawings may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed in turn or alternately with other steps or at least a part of the sub-steps or stages of other steps.

[0065] The above is only a partial implementation method of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A design method for terrain fitting and elevation interpolation along a rail transit line, characterized in that: include: S100, importing a topographic map file, extracting elevation point data therein, and forming an original elevation point set; S200, filtering the original elevation point set, excluding points whose positions are out of range or whose elevations are out of standard according to coordinate and elevation data, and obtaining a filtered elevation point set; S300, importing the filtered elevation point set into the improved triangulated network model, initializing the vertex object set, forming a plane rectangular boundary that can envelop all elevation points, inserting the first elevation point into the plane rectangular boundary, dividing to form an initial improved triangulated network model consisting of four boundary triangles, and initializing the triangle surface object set and edge line object set in the model; S400, sequentially inserting the remaining elevation points into the initial improved triangulated network model, successively triangulating the local network where the insertion points are located, and improving the corresponding point, edge, and surface object sets to obtain an improved triangulated network model for fitting the terrain; S500: Based on the improved triangulated network model for fitting terrain, query and perform elevation interpolation calculation on each mileage point on the line plane to obtain elevation data of all mileage points.

2. A design method for terrain fitting and elevation interpolation along a rail transit line according to claim 1, characterized in that: The improved triangulated network model includes three functional component modules: an initial creation module, a positioning query module and a model I / O module.

3. A design method for terrain fitting and elevation interpolation along a rail transit line according to claim 1, characterized in that: The improved triangulated network model also includes three linked list data sets: a vertex object set, an edge object set and a triangle surface object set.

4. A design method for terrain fitting and elevation interpolation along a rail transit line according to claim 3, characterized in that: The vertex object set, edge line object set and triangle surface object set correspond to three subsidiary object models: vertex object model, edge line object model and triangle surface object model respectively.

5. A design method for terrain fitting and elevation interpolation along a rail transit line according to claim 4, characterized in that: The vertex object model is a data carrier of elevation points, and mainly stores the spatial coordinates and other attribute information of terrain elevation points.

6. A design method for terrain fitting and elevation interpolation along a rail transit line according to claim 4, characterized in that: The edge object model does not store entity data, but only stores relationship information and interface modules, including four functional component modules: endpoint relationship management module, two-side triangle relationship management module, spatial relationship determination module and information interpolation calculation module.

7. A design method for terrain fitting and elevation interpolation along a rail transit line according to claim 4, characterized in that: The triangular surface image model does not store entity data, but only stores relationship information and interface modules, including four functional component modules: vertex relationship management module, edge relationship management module, spatial relationship determination module, and triangular interpolation calculation module.

8. A design method for terrain fitting and elevation interpolation along a rail transit line according to any one of claims 1 to 7, characterized in that: Inserting the remaining elevation points into the initial triangulated mesh model in step S400 to obtain an improved triangulated mesh model for fitting the terrain includes: locating the triangle where the insertion point is located through the positioning query module, and then finding all adjacent triangles around the triangle that do not meet the circumscribed circle criterion through recursive calls to the edge-face relationship, erasing the triangle and the adjacent triangles that do not meet the requirements and their adjacent edges from the triangle surface object set and the edge line object set to form a local hole, and then triangulating the hole using the insertion point, adding the newly generated triangles and edges to the triangle surface object set and the edge line object set until all elevation points are inserted, and finally removing the triangle containing the working boundary vertices to obtain an improved triangulated mesh model for fitting the terrain.

9. A design method for terrain fitting and elevation interpolation along a rail transit line according to any one of claims 1 to 7, characterized in that: Step S500 includes: S501, querying each mileage point through the positioning query module, first finding the boundary triangle closest to the first mileage point according to the working boundary, and determining whether the first mileage point is inside the boundary triangle; S502: when the first mileage point is not inside the boundary triangle, first determine the orientation relationship between the first mileage point and the boundary triangle, then search for adjacent triangles in the same direction through the point-edge-face relationship of the boundary triangle, set the adjacent triangle as the current triangle, and then search cyclically on this basis until the triangle where the first mileage point is located is found, and call the interpolation calculation module to obtain the elevation data of the first mileage point; when the first mileage point is inside the boundary triangle, directly call the interpolation calculation module to obtain the elevation data of the first mileage point; S503, continue to query the next mileage point. The positioning triangle of the next mileage point does not need to start from the working boundary. It only needs to start searching from the positioning triangle of the previous mileage point until the query of each mileage point is completed and the elevation interpolation calculation is completed.

10. A design system for terrain fitting and elevation interpolation along a rail transit line, characterized in that: include: The first module is used to import the topographic map file, extract the elevation point data therein, and form an original elevation point set; The second module is used to perform data screening on the original elevation point set, exclude points whose positions are out of range or whose elevations exceed the standard according to the coordinate and elevation data, and obtain a screened elevation point set; The third module is used to import the filtered elevation point set into the improved triangulated network model, initialize the vertex object set, form a plane rectangular boundary that can envelop all elevation points, insert the first elevation point into the plane rectangular boundary, divide and form an initial improved triangulated network model consisting of four boundary triangles, and initialize the triangle surface object set and edge line object set in the model; The fourth module is used to sequentially insert the remaining elevation points into the initial improved triangulated network model, successively triangulate the local network where the insertion points are located, and improve the corresponding point, edge, and surface object sets to obtain an improved triangulated network model for fitting the terrain; The fifth module is used to query and perform elevation interpolation calculation on each mileage point on the line plane based on the improved triangulated network model for fitting the terrain, so as to obtain the elevation data of all mileage points.

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