Method for high-precision drawing of water conservancy and hydropower terrain section graph

Abstract

The application provides a method for high-precision drawing of water conservancy and hydropower terrain section maps, and belongs to the technical field of cartography and geographic information system, and the steps are as follows: 1) vector section data file preparation and setting; 2) completion of three-dimensional information calculation based on vector data; 3) conversion calculation of section map data information according to three-dimensional information calculation results; 4) completion of analysis and calculation of information on the map according to the parameter requirements such as the scale of the section map; 5) completion of section profile entity drawing of a large amount of section maps in batches according to parameters; and 6) completion of map decoration marking according to the requirements of section map elements such as stake numbers. The application is based on high-precision geographic space three-dimensional vector data files and section layout files, calculates section drawing element information by using geographic space topological relations, and realizes a method for automatically drawing water conservancy section maps in batches with large data. The method is suitable for various data sources, minimizes manual intervention, and improves data production quality and efficiency.

Description

Technical Field

[0001] This invention belongs to the field of cartography and geographic information system technology, and provides a method for high-precision drawing of topographic cross-section maps of water conservancy and hydropower projects. Background Technology

[0002] In the planning, design, and surveying phases of water conservancy projects, there is a high demand for longitudinal and transverse cross-sectional results based on topography, frequently requiring the collection, processing, and drawing of cross-sectional data. Currently, there are various methods for acquiring cross-sectional information, including field surveying, topographic map processing and extraction, digital 3D terrain models, 3D laser scanning point clouds, unmanned underwater vehicle surveying, and digital elevation models, all of which can achieve cross-sectional data acquisition. However, there is a lack of methods for generating large-scale, batch-based cross-sectional maps based on this data acquisition.

[0003] Water conservancy construction, especially water diversion and farmland irrigation projects, often requires the production of cross-sectional data spanning hundreds or even thousands of kilometers. Therefore, a large-scale, automated cross-sectional map production technology is urgently needed to address the issues of efficiency and quality in large-scale projects. Thus, combining current data acquisition methods with a comprehensive analysis of project production needs, it is essential to develop a method for producing large-scale, batch-processed, precise water conservancy and hydropower topographic cross-sections based on high-precision cross-sectional data acquisition. This method would meet the engineering needs of the planning and design phase of water conservancy and hydropower projects. Summary of the Invention

[0004] This invention addresses the bottleneck issues of output quality and production efficiency caused by the previous semi-automatic method of drawing cross-section maps one cross-section at a time from high-precision cross-sectional vector data. It proposes a method for drawing high-precision topographic cross-section maps for water conservancy and hydropower projects. This method utilizes geospatial topological relationships to batch-process the calculation of 3D cross-sectional information, cross-section map output information, cross-section map on-map information, and the drawing and finishing of cross-section profiles from high-precision cross-sectional vector data, resulting in standardized cross-section map outputs. This method achieves high-quality and accurate topographic cross-section map drawing while significantly improving production efficiency through automated batch processing, thereby freeing up labor and reducing production costs. It provides convenience for supporting earthwork calculations, river depth variation analysis, and river flow analysis in water conservancy engineering planning and surveying design.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for high-precision mapping of topographic cross-sections of water conservancy and hydropower projects includes the following steps:

[0007] 1) Preparation and setting of vector section data files;

[0008] 2) Perform three-dimensional information calculations based on vector data;

[0009] 3) Perform cross-sectional data conversion calculations based on the 3D information calculation results;

[0010] 4) Analyze and calculate the information on the map according to the required parameters such as the scale of the cross-section;

[0011] 5) Batch drawing of large quantities of cross-sectional view entities according to parameters;

[0012] 6) Complete the finishing and marking of the drawings according to the requirements of cross-sectional elements such as station number.

[0013] The beneficial effects of this invention are as follows:

[0014] This invention provides a method for automatically generating large-scale hydraulic cross-section maps by using high-precision geospatial 3D vector data files and cross-section layout files as a basis, and calculating cross-section drawing element information using geospatial topological relationships. This method is adaptable to various data sources, minimizes manual intervention, improves data production quality and efficiency, and fills some gaps in the current application characteristics of water conservancy engineering planning and surveying and design stages. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating the implementation of a method for high-precision mapping of topographic cross-sections of water conservancy and hydropower projects.

[0016] Figure 2 This is a cross-section layout diagram, containing information such as cross-section layout lines and cross-section elevation points. The letters in the diagram have the following meanings: A: Longitudinal layout line; B: Transverse layout line; C: Cross-section elevation point; D: Marking of the starting mileage of the longitudinal layout line; E: Name of the longitudinal section; F: Name of the transverse section (named after the mileage of the intersection of the transverse and longitudinal layout lines); G: Intersection point of the transverse and longitudinal layout lines.

[0017] Figure 3 These are important layout information markers in the cross-sectional layout diagram.

[0018] Figure 4 This shows the distribution relationship of key elements in the cross-sectional diagram.

[0019] Figure 5 The result of drawing the cross-sectional lines for the cross-sectional view.

[0020] Figure 6 Setting parameters for cross-sectional view decoration and finishing marking information

[0021] Figure 7 Create case study diagrams for batch cross-sections. Detailed Implementation

[0022] To make the problem solved by the present invention, the method adopted, and the effect achieved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings, not all of them.

[0023] Figure 1 This is a flowchart illustrating the implementation of a method for high-precision mapping of topographic cross-sections of water conservancy and hydropower projects, as provided in this embodiment of the invention. The following describes some basic information about the resulting topographic cross-sections of water conservancy and hydropower projects:

[0024] The topographic cross-section results for water conservancy and hydropower projects include cross-section layout maps and cross-section diagrams, as follows: Figure 2 , Figure 6 As shown. The cross-section layout diagram includes cross-section layout lines and other elements. The cross-section layout lines are divided into longitudinal and transverse layout lines. There is usually only one longitudinal layout line, while there are N transverse layout lines depending on the specific needs, such as... Figure 2 As shown; the cross-sectional diagram output includes the cross-sectional lines and other elements of the cross-sectional diagram. The cross-sectional lines are drawn as a sectional line based on the cross-sectional layout lines, converted and calculated according to the drawing requirements, such as... Figure 5 As shown. The present invention aims to achieve the process of drawing 1+N cross-sectional diagrams by using advanced automated and batch processing techniques.

[0025] According to such Figure 1 The flowchart shown illustrates a method for high-precision mapping of water conservancy and hydropower topographic sections provided by this embodiment of the invention, which includes:

[0026] The first step is to prepare and set up the vector cross-section data file.

[0027] (1) Data preparation.

[0028] It includes vector cross-section elevation point entity data and cross-section layout line data extracted from high-precision digital 3D terrain model data.

[0029] (2) Data preprocessing.

[0030] Ensure that the vector cross-section elevation point entity data is completely aligned with the cross-section layout lines; ensure that the longitudinal layout line mileage stationing is accurate; ensure that the transverse layout line stationing is correct; ensure that there are cross-section elevation point entities at the intersection points of the longitudinal and transverse cross-section layout lines; and ensure that there are cross-section elevation point entities at the apex of the longitudinal layout line. If any defects are found, the causes must be analyzed first, and the reliability of the basic data and the connection between the cross-section layout lines and data acquisition issues must be checked. Preprocessing of the cross-section map layout results can be achieved through comparison, interactive supplementation, modification, and correction.

[0031] The final basic data result, the cross-sectional layout map, is as follows: Figure 2 As shown.

[0032] The second step is to perform three-dimensional information calculations based on vector data.

[0033] Based on the longitudinal and transverse section layout lines, station information, and their inter-geographical spatial relationships, the 3D coordinate files of the section elevation points are calculated and stored in an Excel file. The specific method is as follows:

[0034] (1) Obtain all cross-sectional elevation points on longitudinal line A by overlaying geospatial data;

[0035] Extract all vertices a(x) on the longitudinal section line A. i y i ), traverse the set of entity c(x) of all line segments between two vertices of the longitudinal section and the cross-sectional elevation points. i y i Find the points on the longitudinal profile line by identifying the collinear relationships between the points and the points on the longitudinal profile line, and add them to the entity set Zc(x) of the elevation points on the longitudinal profile line. i y i )middle.

[0036] Let the coordinates of the two vertices of the longitudinal section be (x1, y1) and (x2, y2), and the coordinates of one of the elevation points of the section be (x3, y3). The formula for determining collinearity is as follows:

[0037] (x3*y2-x2*y3)=(x3*y1-x1*y3) (1)

[0038] The final set of cross-sectional elevation points along the longitudinal section layout is Zc(x) i y i ).

[0039] (2) Extract the three-dimensional coordinate information of the longitudinal line in sequence according to the order of the starting mileage station number of the longitudinal line.

[0040] Based on the setting of the starting point of the longitudinal section layout line, the entity set of cross-section elevation points is sorted and arranged.

[0041] (3) Obtain all cross-sectional elevation points on all transverse layout lines B by overlaying geospatial data.

[0042] The determination of the cross-sectional elevation points on the cross-sectional layout line is the same as that for the longitudinal section layout line.

[0043] (4) The principle of the sequence of starting and ending points of the cross-section layout.

[0044] Stand at the starting point of the longitudinal section layout line and face the ending point of the longitudinal section layout line. The left side is the starting point and the right side is the ending point. Calculate the three-dimensional coordinate information of the transverse section line in sequence.

[0045] (5) Save the data in Excel format, using the longitudinal and transverse sections as units. The format of the results is shown in Table 1.

[0046] Table 1 Three-dimensional coordinate information of the cross-section

[0047]

[0048]

[0049] Note: The East and North coordinates in Table 1 are the plane rectangular coordinates after the results have been Gauss-Kruger projection; G in the intersection markers represents the data point at the intersection of the longitudinal and transverse sections; multiple data groups are naturally separated by marking the first column with the section name as the first part followed by the section data information; the first group of data is the longitudinal section data information, followed by N groups of transverse section data information.

[0050] The third step is to convert and calculate the cross-sectional data information based on the results of the three-dimensional information calculation.

[0051] A cross-sectional diagram is a map that uses the mileage data from the current location to the starting point of the cross-section as the horizontal axis and the elevation value of the cross-section point as the vertical axis. This step describes the data calculation methods and procedures for converting three-dimensional information data into mileage and elevation values. Figure 3 This is the content marked with cross-sectional layout information in this embodiment.

[0052] (1) Calculation of data conversion between horizontal and vertical coordinates of longitudinal layout line section diagram

[0053] like Figure 3 As shown, let the set of cross-sectional elevation points along all longitudinal sections be Zc(xi, yi), and let each point be numbered z1, z2, z3, z4, ..., z12, z13, ..., zn.

[0054] The distance from the elevation points along the longitudinal section to the starting point z1 of the section needs to be calculated and used as the coordinate value of the horizontal axis.

[0055] First, starting from point z1, calculate the distances between z1 and z2, z2 and z3, z3 and z4...z12 and z13. The formula is as follows:

[0056] Let the coordinates of z1 and z2 be (x1, y1) and (x2, y2), respectively; and let the distance between z1 and z2 be D. 12 The distance between z2 and z3 is D. 23 ...;

[0057] The formula for the distance between z1 and z2 is:

[0058]

[0059] Then, with the mileage value of point z1 being 0.00, the mileage of point z2 is the mileage of z1 + D. 12 The mileage at point z3 is the mileage at point z2 + D. 23 , 。。。 The mileage at point z13 is the mileage at point z12 + D. 1213 .

[0060] (2) Calculation of data conversion between horizontal and vertical coordinates of cross-sectional diagram of cross-section layout line

[0061] The calculation method for cross-sectional lines is similar, except that the starting point for calculating the cross-sectional mileage is different. The mileage of a cross-sectional line is calculated with the intersection of the longitudinal and transverse lines as 0.00 mileage. Facing the end point of the longitudinal line, the left endpoint is the starting point and the mileage is negative, while the right endpoint is the ending point and the mileage is positive.

[0062] like Figure 3 As shown, in N transverse layout lines, each point on each transverse layout line is numbered as b1, b2, b3, b4, b5, ..., bn, and the horizontal and vertical coordinate transformation data is calculated.

[0063] The calculation results of the horizontal and vertical coordinate conversion data of the longitudinal and transverse layout lines are used as the standard values ​​on the cross-section map. The horizontal mileage coordinate is set as BL0 and the vertical elevation value is set as BH0, as shown in Table 2.

[0064] Table 2 Cross-section mileage and elevation information

[0065]

[0066]

[0067] The fourth step is to complete the analysis and calculation of the information on the map according to the required parameters such as the scale of the cross-section map;

[0068] According to actual engineering needs, cross-sectional drawings must be processed according to a certain scale. In the practice of cross-sectional drawing, in order to highlight the trend of cross-section fluctuations, different scales are often set for the horizontal and vertical directions of the cross-section. This invention needs to complete the conversion and calculation from the actual scale on the ground to the scale drawn on the drawing, based on the set drawing scale. The specific method is as follows:

[0069] (1) Perform independent calculations on 1+N cross-section layout lines and calculate the zero starting coordinates.

[0070] Using a single cross-section layout line as the unit, the starting point of the cross-section layout line is set as (0,0), and coordinate calculations are performed using a drawing scale of 1:1. This step solves the problem of data format uniformity. Its calculation method is simple, only requiring the difference between the starting point mileage station number, elevation value and (0,0) value, and then simple addition and subtraction can be performed.

[0071] (2) Perform independent calculations on the 1+N cross-section layout lines and calculate the scale ratio on the map.

[0072] Since the horizontal and vertical drawing scales can be different, the horizontal scale for the cross-sectional drawing is set to 1:a, and the vertical scale is set to 1:b, respectively, to complete the calculation of the coordinates on the drawing based on the actual drawing scale. The values ​​of a and b are generally set as parameters based on multiples of 100, such as 100, 200, 500, and 1000, according to the actual needs of the engineering construction.

[0073] To facilitate the use of data later, the unit of length for actual coordinates is set to meters (m), and the unit of length for coordinates on the map is millimeters (mm). Therefore, the scale is converted according to the coordinate unit on the map as follows: horizontal scale is 1 (mm): a / 1000 (m), and vertical scale is 1 (mm): b / 1000 (m).

[0074] Set the current true scale zeroing mileage and elevation coordinates to (L0, H0), and the current map scale zeroing mileage and elevation coordinates to (TL0, TH0).

[0075] The relationship between the coordinates on the horizontal plot and the zero-scale coordinates of the true scale is obtained:

[0076]

[0077] The relationship between the coordinates on the vertical plot and the zero-scale coordinates of the true scale is obtained:

[0078]

[0079] The results were obtained through calculation, as shown in Table 3.

[0080] Table 3. Results of relative coordinate calculation on the cross-sectional view.

[0081]

[0082]

[0083] Table 3 sets the horizontal drawing scale to 1:1000 and the vertical drawing scale to 1:100.

[0084] (3) Calculate the height h of the cross-section line drawn on the diagram for each of the 1+N cross-section layout lines. iThat is, calculating the difference between the maximum and minimum values ​​of the longitudinal coordinates on each cross-sectional line diagram, such as... Figure 4 As shown.

[0085] This value is calculated to obtain the minimum area occupied by each cross section in the 1+N cross sections, so as to facilitate the calculation of the position and layout settings of adjacent cross section drawings.

[0086] For example, calculating the cross-sectional height of the center longitudinal section:

[0087] h i =max(TL0) i ,TH0 i )-min(TL0 i ,TH0 i (5)

[0088] Where i = 1 + N. 1 represents one longitudinal line and N represents N transverse lines.

[0089] (4) Perform overall calculation and layout of all cross-section layout lines to form complete basic data for batch cross-section drawing.

[0090] like Figure 4 , Figure 5 , Figure 6 As shown, the cross-sectional map output includes key elements such as cross-sectional line elements, elevation and mileage information area elements, grid elevation axis drawing area elements, and cross-sectional annotation information area elements.

[0091] like Figure 4 As shown, the minimum horizontal distance *e* and minimum vertical distance *f* from the origin "0" of the coordinate axis to the cross-section line of a single cross-section are set. To complete the calculation, the spacing *c* between adjacent cross-sections is set, that is, the vertical distance *c* from the highest point of the current cross-section line along the vertical axis to the origin "0" of the coordinate axis of the previous cross-section is set. This is based on the height set *h* of each cross-section line. i The relative coordinates of the entire series of cross-sections are plotted with the starting coordinates of the first cross-section line as (0,0) and the other cross-sections as related layouts.

[0092] Through such Figure 4 The logical geometric relationships between the parameters shown and the setting of the spacing value c between adjacent cross-sections are used to complete the integrated coordinate information calculation and conversion of the entire set of cross-section data, making final preparations for the next step of drawing the cross-section entity.

[0093] The fifth step is to batch draw a large number of cross-sectional view entities according to the parameters.

[0094] (1) Set the starting position of the first cross-section coordinate axis and obtain the starting coordinates (dx, dy) of the first cross-section through interactive drawing area. This can be done by manual input or by clicking the coordinates with the mouse in the first step of drawing.

[0095] (2) Convert the preset starting coordinates (0,0) of the first section line in step 4 into the actual starting coordinates (dx, dy), and update the drawing data of the entire series of section data by calculating the difference between the horizontal and vertical axes.

[0096] (3) Draw the cross-sectional lines of the cross-section diagram according to the updated drawing data, and mark the intersection of the longitudinal and transverse lines with “▽” (0 point marking of the transverse layout line).

[0097] Cross-sectional view plotting is achieved using the computer graphics-aided design function pline(TL0). i ,TH0 i ) Iterate through the data of each cross section to draw the graph, such as Figure 5 As shown.

[0098] Step 6: Complete the finishing and marking of the drawings according to the requirements of cross-sectional elements such as station number;

[0099] (1) Grid and elevation axis drawing and finishing.

[0100] like Figure 6 As shown, starting from the origin "0" of the coordinate axis, the distance s from the elevation axis to the starting point is set. Based on the current height hi of the cross-section, the cross-section grid, elevation axis, and elevation axis labels are drawn by setting geometric relationships.

[0101] (2) Drawing and finishing of elevation and mileage information.

[0102] The elevation and mileage information area includes three aspects: mileage markings, elevation markings, and ground condition markings. The mileage and elevation markings are the content calculated in the third step, with mileage BL0 and elevation BH0; the ground condition markings include ground condition information corresponding to cross-sections that require special explanation, including vegetation information.

[0103] like Figure 6 As shown, the drawing settings for this area are based on the origin "0" of the coordinate axis, with a downward extension dimension k, aligned with the elevation axis to the west, a width of q, and a total width of p for the three rows of information lists; the length to the east is aligned with the east elevation axis.

[0104] (3) Drawing and finishing of cross-sectional annotation information.

[0105] The cross-section annotation information includes two parts: the current cross-section name and the cross-section scale information. The cross-section name is aligned left-hand with the west elevation axis and upwards at a distance of g; the cross-section scale information is aligned right-hand with the east elevation axis and upwards at a distance of v. Relevant parameter relationships are as follows: Figure 6 , Figure 7 As shown.

[0106] This invention proposes a method for high-precision mapping of topographic cross-sections in water conservancy and hydropower projects. Through geospatial analysis and calculation, it achieves the goal of automated, batch mapping of standard topographic cross-sections from high-precision topographic data. This method changes the outdated, semi-automatic method of mapping cross-sections one by one, solving the problems of low output quality and low production efficiency caused by traditional methods for a considerable period. It has been well-appointed in water conservancy engineering planning and surveying and design, supporting earthwork calculations, river depth variation analysis, and river flow analysis. It achieves efficient and accurate data production, saving manpower and time costs for relevant units to better serve the economic construction of the new era.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the method solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications to the method solutions described in the foregoing embodiments, or equivalent substitutions for some or all of the method features, do not cause the essence of the corresponding method solutions to deviate from the scope of the method solutions of the embodiments of the present invention.

Claims

1. A method for high-precision drawing of topographic cross-section maps of water conservancy and hydropower projects, characterized in that, Includes the following steps: The first step is to prepare and set up the vector section data file; (1) Data preparation; It includes vector cross-section elevation point entity data and cross-section layout line data extracted from high-precision digital 3D terrain model data; (2) Data preprocessing; Ensure that the vector cross-section elevation point entity data is completely aligned with the cross-section layout line; ensure that the mileage station number of the longitudinal layout line is set accurately; ensure that the station number of the transverse layout line is correct; ensure that there are cross-section elevation point entities at the intersection of the longitudinal and transverse cross-section layout lines; and ensure that there are cross-section elevation point entities at the apex of the longitudinal layout line. If there are any defects, check the reliability of the basic data and the connection between the cross-section layout line and the data acquisition. Use interactive supplementation, modification, and correction methods to preprocess the cross-section map layout results. The second step is to perform three-dimensional information calculations based on vector data; Based on the longitudinal and transverse section layout lines, station information, and their respective geographic spatial relationships, the 3D coordinate files of the section elevation points are calculated and stored in an Excel file; the specific method is as follows: (1) Obtain all cross-sectional elevation points on longitudinal section line A by overlaying geospatial data; Extract all vertices a(x) on the longitudinal section line A. i y i ), traverse the set of entities c(x) of line segments between all two vertices of the longitudinal section and the cross-sectional elevation points. i y i Find the points on the longitudinal profile line and select them into the longitudinal profile line elevation point entity set Zc(x) based on the collinear relationship between the points. i y i )middle; Let the coordinates of the two vertices of the longitudinal section be (x1, y1) and (x2, y2), and the coordinates of one of the elevation points of the section be (x3, y3). The formula for determining collinearity is as follows: (x3 y2-x2 y3)=(x3 y1-x1 y3) (1) The final set of cross-sectional elevation points along the longitudinal section layout is Zc(x) i y i ); (2) Extract the three-dimensional coordinate information of the longitudinal line in sequence according to the order of the starting mileage station number of the longitudinal line; Based on the setting of the starting point of the longitudinal section layout line, the entity set of cross-section elevation points is sorted and arranged. (3) Obtain all cross-sectional elevation points on all transverse layout lines B by overlaying geospatial data; The determination of the cross-sectional elevation points on the cross-sectional layout line is the same as that of the longitudinal section layout line. (4) The principle of the sequence of the start and end points of the transverse layout; Stand at the starting point of the longitudinal section layout line and face the ending point of the longitudinal section layout line. The left side is the starting point and the right side is the ending point. Calculate the three-dimensional coordinate information of the transverse section line in sequence. (5) Save Excel files in units of longitudinal and transverse cross-section layout lines; In the intersection marker, G represents the data point at the intersection of the longitudinal and transverse sections; multiple data groups are naturally separated by marking the first column, each starting with the section name followed by the section data information; the first group of data is the longitudinal section data information, followed by N groups of transverse section data information; The third step is to convert and calculate the cross-sectional data information based on the results of the three-dimensional information calculation. A cross-sectional diagram is a map that uses the mileage data from the current location to the starting point of the cross-section as the horizontal axis and the elevation value of the cross-section point as the vertical axis; it also includes the data calculation methods and steps for converting three-dimensional information data into mileage and elevation values. (1) Calculation of data conversion between horizontal and vertical coordinates of longitudinal section diagram Let Zc(xi, yi) be the entity set of cross-sectional elevation points on all longitudinal profile lines, and let each point be numbered z1, z2, z3, z4, ..., z12, z13, ..., zn; Calculate the distance from the elevation point entity along the longitudinal layout line to the starting point z1 of the layout line, and use it as the coordinate value of the horizontal axis; First, starting from point z1, calculate the distances between z1 and z2, z2 and z3, z3 and z4...z12 and z13; let the coordinates of z1 and z2 be (x1, y1) and (x2, y2), respectively; and let the distance between z1 and z2 be D. 12 The distance between z2 and z3 is D. 23 ...; then the formula for the distance values ​​of z1 and z2 is: （2） Then, with the mileage value of point z1 being 0.00, the mileage of point z2 is z1 mileage + D. 12 The mileage at point z3 is the mileage at point z2 + D. 23 ..., the mileage at point z13 is the mileage at point z12 + D 1213 ; (2) Calculation of cross-sectional coordinate conversion data for cross-sectional layout line The calculation method for cross-sectional layout lines is similar, except that the starting point for cross-sectional mileage is different; the mileage of the cross-sectional line is 0.00 mileage at the intersection of the longitudinal and transverse lines, facing the end of the longitudinal line, with the left end point as the starting point and the mileage as negative, and the right end point as the ending point and the mileage as positive. In N transverse layout lines, each point on the transverse layout line is numbered as b1, b2, b3, b4, b5, ..., bn, and the horizontal and vertical coordinate transformation data is calculated. The calculation results of the horizontal and vertical coordinate conversion data of the longitudinal and transverse layout lines are used as the standard values ​​on the cross-section map. The horizontal mileage coordinate is set as BL0 and the vertical elevation value is set as BH0. The fourth step is to complete the analysis and calculation of the information on the map according to the requirements of the cross-sectional map scale parameters; Based on the drawing scale, complete the conversion and calculation from the actual scale on the ground to the scale drawn on the map: (1) Perform independent calculations on 1+N cross-sectional layout lines and calculate the zero starting coordinates; Using a single cross-section layout line as the unit, the starting point of the cross-section layout line is set as (0,0), and coordinate calculations are performed with a drawing scale of 1:

1. To solve the problem of data format uniformity, we only need to find the difference between the starting mileage station number, elevation value and (0,0) value, and then perform simple addition and subtraction to reduce it; (2) Perform independent calculations on the 1+N cross-sectional layout lines and calculate the scale ratio on the map; Set the horizontal scale of the cross-sectional view to 1:a and the vertical scale to 1:b, and complete the coordinate calculation on the map according to the actual drawing scale; among which... The values ​​of a and b are set according to the actual needs of the project construction; The actual coordinate unit is set to meters (m), and the coordinate unit on the map is millimeters (mm). Therefore, the scale is converted according to the coordinate unit on the map as follows: the horizontal scale is 1 (mm): a / 1000 (m), and the vertical scale is 1 (mm): b / 1000 (m). Set the current true scale zeroing mileage and elevation coordinates to (L0, H0), and the current map scale zeroing mileage and elevation coordinates to (TL0, TH0). The relationship between the coordinates on the horizontal plot and the zero-scale coordinates of the true scale is obtained: （3） The relationship between the coordinates on the vertical plot and the zero-scale coordinates of the true scale is obtained: （4） The calculation results of the relative coordinates on the cross-sectional drawing are obtained through calculation. (3) Calculate the height h of the cross-section line drawn on the diagram for each of the 1+N cross-section layout lines. i That is, to calculate the difference between the maximum and minimum values ​​of the longitudinal coordinates on each cross-sectional line diagram; This value is calculated to obtain the minimum area occupied by each section of the 1+N sections for drawing the cross-sectional view, and is used to calculate the position and layout settings of adjacent cross-sectional views. The cross-sectional height of the center longitudinal section is calculated using the following formula: （5） Where i = 1 + N; 1 is a longitudinal section layout line, and N is N transverse section layout lines; (4) All cross-section layout lines are calculated and laid out in a unified manner to form complete batch cross-section drawing basic data. The cross-section results include cross-section line elements, elevation mileage information area elements, grid elevation axis drawing area elements, and cross-section annotation information area elements. Set the minimum horizontal distance *e* and minimum vertical distance *f* from the origin "0" of the coordinate axis to the cross-section line of a single cross-section diagram. To complete the calculation, set the spacing *c* between adjacent cross-section diagrams, which is the vertical distance *c* from the highest point of the current cross-section line along the vertical axis to the origin "0" of the coordinate axis of the previous cross-section diagram. Based on the height set *h* of each cross-section line... i The calculation of relative coordinates for the entire series of cross-sections with the starting coordinates of the first cross-section line as (0,0) and the associated layout of other cross-sections is completed. Finally, the integrated coordinate information calculation and conversion of the entire set of cross-section data is completed, which is the final preparation for the next step of drawing cross-section entities. The fifth step is to batch draw a large number of cross-sectional view entities according to the parameters. (1) Set the starting position of the first cross-section coordinate axis and obtain the starting coordinates (dx, dy) of the first cross-section through interactive drawing area; (2) Convert the preset starting coordinates (0,0) of the first section line in step 4 into the actual drawing starting coordinates (dx, dy), and update the drawing data of the entire series of section data by calculating the difference between the horizontal and vertical axes; (3) Draw the cross-sectional lines of the cross-section diagram according to the updated drawing data, and mark the intersection of the longitudinal and transverse lines with "▽" and the 0 point of the transverse layout line; Step 6: Complete the finishing and marking of the drawings according to the requirements of cross-sectional elements such as station number; (1) Grid and elevation axis drawing finishing touches; Starting from the origin "0" of the coordinate axis, set the distance s from the elevation axis to the starting point, and based on the current height hi of the cross-section, complete the drawing of the cross-section grid, elevation axis and elevation axis labels through geometric relationships; (2) Drawing and finishing of elevation and mileage information; The elevation and mileage information area includes three aspects of information: mileage markings, elevation markings, and ground condition markings. The mileage and elevation markings are the contents of the third step of calculation, with mileage BL0 and elevation BH0. The ground condition markings include ground condition information corresponding to cross sections that require special explanation, including vegetation information. (3) Drawing and finishing of cross-section annotation information, including the current cross-section name and the cross-section longitudinal and transverse scale information.

Images