A method, system and apparatus for checking contour gradients
By acquiring and storing the relationships between adjacent contour lines during contour line inspection, the problems of low efficiency and low accuracy in traditional manual inspection are solved, achieving efficient and accurate contour line and contour interval inspection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SOUTH SURVEYING & MAPPING INSTR
- Filing Date
- 2022-08-09
- Publication Date
- 2026-06-02
Smart Images
Figure CN115455221B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of surveying and mapping technology, and more specifically, to a method, system, and device for checking contour gradients. Background Technology
[0002] Contour lines are closed curves connecting adjacent points of equal elevation on a topographic map. In cartographic work, maps are currently primarily created based on field survey data, which requires drawing key features—contour lines. To create qualified graphic files that meet standard map requirements and specific operational needs, contour lines need to be trimmed, moved, and have their elevation values modified. Due to these manual operations, incorrect contour line elevation values can occur, causing the contour interval between adjacent contour lines to differ from the set value. Therefore, it is necessary to check the contour interval of adjacent contour lines.
[0003] Traditional contour line inspection mainly relies on quality inspectors visually observing computer screens or paper maps, judging whether points and lines contradict each other based on experience. This method is not only labor-intensive and inefficient, but even after multiple review processes, misjudgments and omissions can still occur. Summary of the Invention
[0004] To overcome the shortcomings of low work efficiency and low judgment accuracy in the above-mentioned prior art of manually checking contour lines and contour intervals, the present invention provides a method, system and equipment for checking contour gradients.
[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:
[0006] A contour gradient checking method includes the following steps:
[0007] S1. Obtain all contour line entities and corresponding contour line information on the target topographic map;
[0008] S2. For contour line entity i, determine whether contour line entity i and its contour line information have been stored in a cache unit:
[0009] If not, then search for adjacent contour lines along the gradient descent direction for contour line entity i, and store the matching adjacent contour lines and their contour line information in the cache unit that matches contour line entity i.
[0010] If so, then execute step S3; where i = 1, 2, ..., N, and N is the total number of contour line entities;
[0011] S3. Based on the cache unit that stores contour line entity i and its contour line information, or the corresponding cache unit of contour line entity i, find the upper and lower contour lines of contour line entity i.
[0012] If there are upper and lower contour lines, the contour interval of adjacent upper and lower contour lines will be compared with the set value, and the comparison result will be stored.
[0013] If no upper or lower contour lines exist, proceed to step S4;
[0014] S4. Check the next contour line entity i = i+1, and repeat steps S2 to S4 until all contour line entities have been checked; display the comparison results of the upper and lower contour lines of the target contour line entity.
[0015] As a preferred embodiment, the contour information includes the ID, height value, checkpoint set, first derivative set of checkpoints, and ID, height value, and special line symbol ID of each contour entity surrounding the contour entity.
[0016] As a preferred embodiment, step S2, which involves searching for adjacent contour lines along the gradient descent direction of contour line entity i, includes:
[0017] S2.1.1. Based on the set of checkpoints and the set of first derivatives of the checkpoints of contour line entity i, draw the left and right normals for any checkpoint j on contour line entity i; where j = 1, 2, ..., M i M i The total number of checkpoints for contour line entity i;
[0018] S2.1.2 Determine whether the left and right normals of any checkpoint j on contour line entity i intersect with surrounding contour line entities and / or special line symbol entities:
[0019] If so, calculate the distance between the intersection point and the checkpoint, and store the distance value, the ID of the intersecting contour line entity and its height value, and / or the ID of the intersecting special line symbol entity and its height value in the cache unit that matches the contour line entity i, in the order of the distance value.
[0020] Otherwise, the next checkpoint j = j + 1 is judged until all checkpoints have completed the search for adjacent contour lines.
[0021] As a preferred embodiment, step S3 specifically includes the following steps:
[0022] S3.1. From the cache unit storing contour line entity i and its contour line information, find the adjacent contour line that is close to the id of contour line entity i as the upper and lower contour lines, and extract its id and height value; or from the corresponding cache unit of contour line entity i, find the adjacent contour line with the largest distance value from contour line entity i as the upper and lower contour lines, and extract its id and height value.
[0023] If no adjacent contour lines can be found, it means that there are no upper and lower contour lines, and step S4 is executed;
[0024] S3.2. Compare the contour interval of the upper and lower contour lines with the set value. If the contour interval is equal to the set value or the difference is within the preset deviation range, the contour interval is judged to be correct and the judgment result is stored in the inspection result list; otherwise, the contour interval is judged to be incorrect and the judgment result is stored in the inspection result list.
[0025] As a preferred embodiment, the special line symbol includes the steep slope or incline line symbol U; step S2.1.2 further includes the following steps:
[0026] When the left and right normals of checkpoint j intersect with the symbol U of the steep slope or incline, calculate the distance d1 between checkpoint j and the intersection point;
[0027] When the distance between the intersection point of a surrounding contour line entity or special line symbol entity and the check point j is greater than the distance value d1, the corresponding surrounding contour line entity or special line symbol entity is deleted from the cache unit.
[0028] As a preferred embodiment, step S2.1.2 further includes the following step:
[0029] When the left and right normals of checkpoint j intersect with the surrounding contour entities at two or more points, calculate the distance between any intersection point and the checkpoint, retain the contour entity ID and its height value with the smallest distance value in the corresponding cache unit, and delete the other contour entity IDs and their height values.
[0030] Furthermore, the present invention also proposes a contour gradient checking system, applying the contour gradient checking method proposed in any of the above-mentioned technical solutions, including:
[0031] The data reading module is used to acquire all contour line entities and corresponding contour line information on the target topographic map;
[0032] Several cache units are used to store the contour information of adjacent contour lines of the corresponding contour line entity;
[0033] The lookup module is used to look up the ID of the target contour line entity from the cache unit; if the cache unit already stores the contour line information of the target contour line entity, it sends a working signal to the adjacent judgment unit; otherwise, it sends a working signal to the intersection judgment module.
[0034] The intersection judgment module is used to draw the left and right normals of any checkpoint in the target contour line entity, and determine whether the left and right normals of the checkpoint intersect with the surrounding contour line entities and / or special line symbol entities. If they do, the distance value between the intersection point and the checkpoint is calculated, and the distance value, the ID of the intersecting contour line entity and its height value, and / or the ID of the intersecting special line symbol entity and its height value are stored in the cache unit that matches the contour line entity i in the order of the distance value. Otherwise, the next checkpoint is judged until all checkpoints have completed the search for adjacent contour lines.
[0035] The contour interval checking module is used to find the upper and lower contour lines of the target contour line entity based on the cache unit that stores the target contour line entity and its contour line information, or the corresponding cache unit of the target contour line entity, and to determine whether the contour interval of the upper and lower contour lines is correct, and output the contour interval judgment result of the upper and lower contour lines.
[0036] The display module is used to display the upper and lower contour lines of the target contour line and the judgment result of the contour interval.
[0037] As a preferred embodiment, the system further includes a filtering module, which comprises:
[0038] The first filtering unit is used to delete the surrounding contour line entities or special line symbol entities with larger distance values when the left and right normals of check point j intersect with the steep slope or ramp line symbol U, and retain the surrounding contour line entities or special line symbol entities with the smallest distance value in the cache unit.
[0039] The second filtering unit is used to retain the contour entity ID and its height value with the smallest distance value in the corresponding cache unit when the left and right normals of check point j have more than or equal to 2 intersection points with the surrounding contour entities, and delete the other contour entity IDs and their height values.
[0040] As a preferred embodiment, the cache unit includes a map container.
[0041] Furthermore, the present invention also proposes a contour gradient inspection device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the contour gradient inspection method proposed in any of the above-mentioned technical claims.
[0042] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows: The present invention finds the adjacent contour lines along the gradient descent direction of the target contour line entity, and selects the upper and lower contour lines that are closest to the target contour line entity from the found adjacent contour lines. Contour interval checks are performed on the upper and lower contour lines of the target contour line entity, which effectively improves the efficiency and accuracy of contour line interval checks. By storing the relationship between adjacent contour lines, the lag problem caused by repeatedly using CAD selection sets is avoided, and the problem of repeatedly finding intersections and calculating adjacent relationships of contour lines is avoided, thereby greatly reducing the computational cost and improving the efficiency of contour line interval checks. Attached Figure Description
[0043] Figure 1 This is a flowchart of the contour gradient checking method in Example 1.
[0044] Figure 2 This is a flowchart of the contour gradient checking method in Example 1.
[0045] Figure 3 This is an architecture diagram of the contour gradient inspection system in Example 2. Detailed Implementation
[0046] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent.
[0047] To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions;
[0048] It will be understood by those skilled in the art that certain well-known structures and their descriptions may be omitted in the accompanying drawings.
[0049] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.
[0050] Example 1
[0051] This embodiment proposes a contour gradient checking method, such as... Figure 1 , 2 The diagram shown is a flowchart of the contour gradient checking method in this embodiment.
[0052] The contour gradient checking method proposed in this embodiment includes the following steps:
[0053] S1. Obtain all contour line entities and corresponding contour line information on the target topographic map.
[0054] S2. For contour line entity i, determine whether contour line entity i and its contour line information have been stored in a cache unit:
[0055] If not, then search for adjacent contour lines along the gradient descent direction for contour line entity i, and store the matching adjacent contour lines and their information in the cache unit that matches contour line entity i; if yes, then execute step S3; where i = 1, 2, ..., N, and N is the total number of contour line entities in the target topographic map.
[0056] S3. Based on the cache unit storing contour line entity i and its contour line information, or the corresponding cache unit of contour line entity i, find the upper and lower contour lines of contour line entity i:
[0057] If upper and lower contour lines exist, the contour interval of adjacent upper and lower contour lines is compared with the set value, and the comparison result is stored; if no upper and lower contour lines exist, step S4 is executed.
[0058] S4. Check the next contour line entity i = i+1, and repeat steps S2 to S4 until all contour line entities have been checked; display the comparison results of the upper and lower contour lines of the target contour line entity.
[0059] This embodiment searches for adjacent contour lines along the gradient descent direction of the target contour line entity. From these adjacent contour lines, it selects the nearest upper and lower contour lines to the target contour line entity. A contour interval check is performed on these upper and lower contour lines. Contour lines with contour intervals not equal to a preset value or exceeding the deviation range are judged as having incorrect contour intervals or gradients, and the judgment result is displayed. After traversing all contour line entities, gradient checks are performed on all contour lines.
[0060] In this embodiment, the contour information includes the ID, height value, checkpoint set, first derivative set of checkpoints, and ID, height value, and special line symbol ID of each contour entity surrounding the contour entity.
[0061] The set of checkpoints includes the starting point, intermediate point, and ending point of the contour line entity, and the set of first derivatives of the checkpoints includes the slope of the tangent line to the checkpoint on the line.
[0062] In one specific embodiment, contour gradient checks are performed in conjunction with CAD software, and contour information of contour entities is obtained through the CAD's built-in selection set interface.
[0063] Further, in an optional embodiment, the coordinates of the lower left and upper right corners of the contour line are calculated using the set of all points on the contour line entity, resulting in a selection set key F. The selection set key F is the set of contour lines intersecting the rectangle formed by the lower left and upper right corners of the contour line, as well as the set of special line symbols contained within the rectangle. This yields all contour line entities and special line symbol entities surrounding the contour line. Then, through a CAD interface, the entity ID and height value of each surrounding contour line, as well as the entity ID of each special line symbol, are obtained and stored.
[0064] In step S2 of this embodiment, by determining whether the contour line entity i and its contour line information have been stored in a cache unit, it is determined whether the current target contour line entity i has completed the search for adjacent contour lines.
[0065] In an optional embodiment, step S2, which involves searching for adjacent contour lines along the gradient descent direction of contour line entity i, includes:
[0066] S2.1.1. Based on the set of checkpoints and the set of first derivatives of the checkpoints of contour line entity i, draw the left and right normals for any checkpoint j on contour line entity i; where j = 1, 2, ..., M i M i denoted as the total number of checkpoints for contour line entity i.
[0067] S2.1.2 Determine whether the left and right normals of any checkpoint j on contour line entity i intersect with surrounding contour line entities and / or special line symbol entities:
[0068] If so, calculate the distance between the intersection point and the checkpoint, and store the distance value, the ID of the intersecting contour line entity and its height value, and / or the ID of the intersecting special line symbol entity and its height value in the cache unit that matches the contour line entity i, according to the order of the distance value. Otherwise, judge the next checkpoint j = j + 1 until all checkpoints have completed the search for adjacent contour lines.
[0069] In this embodiment, considering that the direction of gradient descent is perpendicular to the tangent direction of the contour line, the left and right normals of the checkpoint are drawn, and the ID of the adjacent contour line is determined according to whether the normal intersects with the adjacent contour line or special symbol.
[0070] Optionally, in this embodiment, the left and right vertical lines, i.e. the left and right normals, of each checkpoint are simulated and drawn based on the checkpoint set and its first derivative set.
[0071] Furthermore, in an optional embodiment, step S2.1.2 further includes the following step:
[0072] When the left and right normals of checkpoint j intersect with the symbol U of the steep slope or incline, calculate the distance d1 between checkpoint j and the intersection point.
[0073] When the distance between the intersection point of a surrounding contour line entity or special line symbol entity and the check point j is greater than the distance value d1, the corresponding surrounding contour line entity or special line symbol entity is deleted from the cache unit.
[0074] The symbol U for steep slopes or inclines is a special symbol.
[0075] This embodiment aims to filter out unreasonable contour lines and special line symbols in the cache unit after completing the intersection calculation. Specifically, this embodiment filters out steep slopes or ramps that are far apart, removing redundant data.
[0076] Furthermore, in an optional embodiment, step S2.1.2 further includes the following steps: when the left and right normals of check point j intersect with the surrounding contour line entities at more than or equal to 2 points, calculate the distance value between any intersection point and the check point, retain the contour line entity ID and its height value with the smallest distance value in the corresponding cache unit, and delete the other contour line entity IDs and their height values.
[0077] The above steps are also used to filter unreasonable contour lines and special line symbols in the cache unit. In this embodiment, it is specifically for the case where there are multiple intersection points, that is, the case where there are multiple adjacent contour lines. The nearest adjacent contour line with the smallest distance value is retained in the corresponding cache unit, and redundant data is deleted.
[0078] After filtering and screening adjacent contour lines in the cache unit, step S3 can determine whether each contour line has an adjacent relationship with other contour lines. The distance value can be used to mark the adjacent relationship between the target contour line entity i and the surrounding contour lines, and then stored.
[0079] Step S3 in this embodiment is used to find the upper and lower contour lines of the current target contour line entity based on the cached units that have been searched, and to perform contour line gradient checks on the upper and lower contour lines.
[0080] In an optional embodiment, step S3 specifically includes the following steps:
[0081] S3.1. From the cache unit storing contour line entity i and its contour line information, find the adjacent contour line that is close to the id of contour line entity i as the upper and lower contour lines, and extract its id and height value; or from the corresponding cache unit of contour line entity i, find the adjacent contour line with the largest distance value from contour line entity i as the upper and lower contour lines, and extract its id and height value; if the adjacent contour line cannot be found, it means that there is no upper and lower contour line, and proceed to step S4.
[0082] S3.2. Compare the contour interval of the upper and lower contour lines with the set value. If the contour interval is equal to the set value or the difference is within the preset deviation range, the contour interval is judged to be correct and the judgment result is stored in the inspection result list; otherwise, the contour interval is judged to be incorrect and the judgment result is stored in the inspection result list.
[0083] In this embodiment, when upper and lower contour lines exist, the adjacency relationship can be determined by judging the distance relationship between a preset value and the corresponding upper and lower contour lines. If no upper or lower contour lines exist, the contour line is considered to exist independently, and the search for the next contour line gradient continues.
[0084] In step S4 of this embodiment, by iterating through all contour line entities, the final comparison result list contains the check results of whether the upper and lower contour lines of any contour line entity have incorrect contour intervals.
[0085] In one specific embodiment, when displaying the inspection results, double-clicking a row in the inspection results list will highlight the two contour lines with incorrect contour intervals corresponding to that row, and simultaneously display the height values of these two contour lines.
[0086] In this embodiment, the intersection of contour lines with the surrounding contour lines is calculated and stored using the left and right normals of the contour line checkpoints. This process determines whether contour lines are adjacent and establishes a contour line storage mechanism to record the set of adjacent contour lines. By storing the relationships between adjacent contour lines, the system avoids the lag issues caused by repeatedly using CAD selection sets and avoids the problem of repeatedly calculating the intersection and adjacency of contour lines, thereby greatly reducing computational costs and improving the efficiency of contour line interval inspection.
[0087] Example 2
[0088] This embodiment proposes a contour gradient checking system, applying the contour gradient checking method proposed in Embodiment 1. For example... Figure 3 The diagram shown is an architecture diagram of the contour gradient inspection system in this embodiment.
[0089] The contour gradient checking system proposed in this embodiment includes a data reading module 1, a cache unit 2, a search module 3, an intersection judgment module 4, a contour interval checking module 5, and a display module 6.
[0090] Among them, the data reading module 1 is used to acquire all contour line entities and corresponding contour line information on the target topographic map.
[0091] In one specific embodiment, the data reading module 1 acquires contour line entities and corresponding contour line information through the CAD platform interface.
[0092] Cache unit 2 is used to store the contour information of adjacent contour lines of the corresponding contour line entity.
[0093] In the cache unit 2 of this embodiment, the stored contour information of adjacent contour lines includes the ID of the contour line entity, the height value, and the ID of the special line symbol entity.
[0094] In one specific embodiment, a map container is used as cache unit 2 to store the contour information of adjacent contour lines of the target contour line entity.
[0095] The lookup module 3 is used to look up the ID of the target contour line entity from the cache unit 2.
[0096] If the target contour information is already stored in the cache unit 2, the search module 3 sends a working signal to the adjacent judgment unit; otherwise, it sends a working signal to the intersection judgment module 4.
[0097] In this embodiment, the search unit determines whether the current target contour entity i has completed the search for adjacent contour lines by judging whether the contour entity i and its contour information have been stored in a cache unit 2.
[0098] The intersection judgment module 4 is used to draw the left and right normals of any checkpoint in the target contour line entity and to determine whether the left and right normals of the checkpoint intersect with the surrounding contour line entities and / or special line symbol entities.
[0099] If so, calculate the distance between the intersection point and the checkpoint, and store the distance value, the ID of the intersecting contour line entity and its height value, and / or the ID of the intersecting special line symbol entity and its height value in the cache unit 2 that matches the contour line entity i, according to the order of the distance value. Otherwise, judge the next checkpoint until all checkpoints have completed the search for adjacent contour lines.
[0100] The intersection judgment module 4 in this embodiment aims to determine adjacent contour lines. It determines the ID of adjacent contour lines by drawing the left and right normals of the checkpoints and determining whether the normals intersect with the adjacent contour lines or special symbols.
[0101] The contour interval checking module 5 is used to find the upper and lower contour lines of the target contour line entity based on the cache unit 2 that stores the target contour line entity and its contour line information, or the corresponding cache unit 2 of the target contour line entity, and to determine whether the contour interval of the upper and lower contour lines is correct, and output the contour interval judgment result of the upper and lower contour lines.
[0102] In this embodiment, the contour interval checking module 5 first determines the contour lines that are adjacent, then checks the contour interval between the upper and lower contour lines, and outputs the contour interval checking results.
[0103] Display module 6 is used to display the upper and lower contour lines of the target contour line and the judgment result of the contour interval.
[0104] Furthermore, in an optional embodiment, the system further includes a filtering module for filtering adjacent contour lines in the cache unit 2.
[0105] The filtering module in this embodiment includes:
[0106] The first filtering unit is used to delete the surrounding contour line entities or special line symbol entities with larger distance values when the left and right normals of check point j intersect with the steep slope or ramp line symbol U, and retain the surrounding contour line entities or special line symbol entities with the smallest distance value in the cache unit 2.
[0107] The second filtering unit is used to retain the contour entity ID and its height value with the smallest distance value in the corresponding cache unit 2 when the left and right normals of check point j have more than or equal to 2 intersection points with the surrounding contour entities, and delete the other contour entity IDs and their height values.
[0108] This embodiment uses an added filtering module to filter unreasonable contour lines and special line symbols in cache unit 2. Specifically, the first filtering unit filters out steep slopes or inclines that are far apart, deleting redundant data; the second filtering unit filters out data with multiple adjacent contour lines, retaining the nearest adjacent contour line with the smallest distance value in the corresponding cache unit 2, deleting redundant data, thereby avoiding the problem of repeatedly calculating the intersection and adjacency relationship of contour lines, reducing computational costs, and improving the efficiency of contour line interval inspection.
[0109] Example 3
[0110] This embodiment proposes a contour gradient inspection device, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the contour gradient inspection method proposed in Embodiment 1.
[0111] The same or similar labels correspond to the same or similar parts;
[0112] The terms used to describe positional relationships in the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent.
[0113] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A method for checking contour gradients, characterized in that, Includes the following steps: S1. Obtain all contour line entities and corresponding contour line information on the target topographic map; the contour line information includes the ID, height value, checkpoint set, first derivative set of checkpoints, and ID, height value, and special line symbol entity ID of each contour line entity surrounding the contour line entity. S2, For contour line entities i Determine the contour lines of the entity i Has its contour information been stored in a cache unit? If not, then for contour lines... i Perform a search for adjacent contour lines along the gradient descent direction, and store the matched adjacent contour lines and their information in the contour line entity. i In the matching cache unit; If so, then execute step S3; where i =1,2,..., N , N This represents the total number of contour line entities. Among them, contour lines i The steps for finding adjacent contour lines along the gradient descent direction include: S2.1.1, Based on contour lines i The set of checkpoints and the set of first derivatives of checkpoints for contour lines. i any checkpoint on j Draw the left and right normals; where j =1,2,..., M i , M i Contour lines i Total number of checkpoints; S2.1.2, Identifying contour line entities i any checkpoint on j Do the left and right normals intersect with the surrounding contour lines and / or special line symbol entities? If so, calculate the distance between the intersection point and the checkpoint, and store the distance value, the ID of the intersecting contour line entity and its height value, and / or the ID of the intersecting special line symbol entity and its height value in the contour line entity according to the order of the distance value. i In the matching cache unit; Otherwise, for the next checkpoint j = j +1 is used for judgment until all checkpoints have completed the search of adjacent contour lines; S3, from the stored contour line entities i Search for the contour entity in the cache unit of its contour information. i The adjacent contour lines with the nearest ID are used as the upper and lower contour lines, and their IDs and height values are extracted; or from the contour line entities... i In the corresponding cache unit, look up the entity corresponding to the contour line. i The adjacent contour line with the largest distance value is used as the upper and lower contour lines, and its ID and height value are extracted. If there are upper and lower contour lines, the contour interval of adjacent upper and lower contour lines will be compared with the set value, and the comparison result will be stored. If no upper or lower contour lines exist, proceed to step S4; S4, for the next contour line entity i=i +1 to perform the check, repeat steps S2~S4 until all contour line entities have been checked; display the comparison results of the upper and lower contour lines of the target contour line entity.
2. The contour gradient checking method according to claim 1, characterized in that, In step S3, the contour interval of adjacent upper and lower contour lines is compared with a set value, including: If the contour interval is equal to the set value or the difference is within the preset deviation range, the contour interval is judged to be correct, and the judgment result is stored in the inspection result list; otherwise, the contour interval is judged to be incorrect, and the judgment result is stored in the inspection result list.
3. The contour gradient checking method according to claim 1, characterized in that, The special line symbols include the steep slope or sloping line symbol U; step S2.1.2 also includes the following steps: When checkpoint j When the left and right normals intersect with the symbol U of the steep slope or ramp, calculate the checkpoint. j Distance value to the intersection point d 1; When there are intersections and checkpoints on surrounding contour lines or special line symbols. j The distance value is greater than the distance value d When 1, the corresponding surrounding contour line entities or special line symbol entities are deleted from the cache unit.
4. The contour gradient checking method according to claim 1 or 3, characterized in that, Step S2.1.2 further includes the following steps: When checkpoint j When the left and right normals of an object intersect with the surrounding contour lines at two or more points, calculate the distance between any intersection point and the checkpoint, retain the contour line entity ID and its height value with the smallest distance value in the corresponding cache unit, and delete the other contour line entity IDs and their height values.
5. A contour gradient checking system, applied to the contour gradient checking method according to any one of claims 1 to 4, characterized in that, include: The data reading module is used to acquire all contour line entities and corresponding contour line information on the target topographic map; Several cache units are used to store the contour information of adjacent contour lines of the corresponding contour line entity; The lookup module is used to look up the ID of the target contour line entity from the cache unit; if the cache unit already stores the contour line information of the target contour line entity, it sends a working signal to the adjacent judgment unit; otherwise, it sends a working signal to the intersection judgment module. The intersection detection module is used to draw the left and right normals of any checkpoint in the target contour entity, and determine whether the left and right normals of the checkpoint intersect with the surrounding contour entities and / or special line symbol entities. If so, it calculates the distance value between the intersection point and the checkpoint, and stores the distance value, the ID of the intersecting contour entity and its height value, and / or the ID of the intersecting special line symbol entity and its height value in the contour entity's database, in order of magnitude. i If a match is found in the cache unit, the next checkpoint is checked; otherwise, the checkpoint is checked until all checkpoints have completed the search for adjacent contour lines. The contour interval checking module is used to find the upper and lower contour lines of the target contour line entity based on the cache unit that stores the target contour line entity and its contour line information, or the corresponding cache unit of the target contour line entity, and to determine whether the contour interval of the upper and lower contour lines is correct, and output the contour interval judgment result of the upper and lower contour lines. The display module is used to display the upper and lower contour lines of the target contour line and the judgment result of the contour interval.
6. The contour gradient inspection system according to claim 5, characterized in that, The system further includes a filtering module, which includes: The first filtering unit is used for checking the checkpoint. j When the left and right normals intersect with the steep slope or ramp symbol U, delete the surrounding contour line entities or special line symbol entities with larger distance values, and retain the surrounding contour line entities or special line symbol entities with the smallest distance value in the cache unit. The second filtering unit is used for the checkpoint. j When the left and right normals of an object intersect with the surrounding contour entities at two or more points, the contour entity ID with the smallest distance value and its height value are retained in the corresponding cache unit, and the other contour entity IDs and their height values are deleted.
7. The contour gradient inspection system according to claim 5, characterized in that, The cache unit includes a map container.
8. A contour gradient inspection device, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the contour gradient checking method according to any one of claims 1 to 4.