A face long-area extraction method, system and storage medium

Abstract

The present application relates to the field of geographic information, especially to a kind of face long area judgment method, system and storage medium, including by converting the processing of entire closed face to the analysis between face node and face edge line, by searching the straight line segment of the closest distance in the preset range and the distance greater than 0 of face node, the position of the closest distance between point line is connected, the connecting line intersecting the straight line segment where the face node is located is obtained, the straight line segment and connecting line are fused after being constructed face, the fusion face is obtained, the face type of the fusion face is judged, sharp angle is removed, and the processing of the aspect ratio is judged, and the final long face is obtained after eliminating the fusion face that does not meet the requirements. The problem that the smaller long area existing cannot be accurately judged is solved.

Description

Technical Field

[0001] This invention relates to the field of geographic information, and in particular to a method, system, and storage medium for determining elongated and narrow regions. Background Technology

[0002] Narrow, elongated areas are a common problem in the field of geographic information systems (GIS). The existence of such areas can cause issues when applying data, such as difficulty in clearly representing it during symbolization. There are many reasons for this phenomenon, including drawing errors, cropping, and tolerance settings during erasure operations. Therefore, land registration and the third national land survey have specific inspection requirements to address this problem.

[0003] To address this issue, one current approach is to use an inward buffering method. This involves comparing the theoretical and actual differences in the perimeter of the shape before and after buffering. If the actual difference is greater than the theoretical difference, the shape is considered a suspected localized elongated shape; if the actual difference is less than the theoretical difference, it is not. However, if the elongated region to be identified is small, this method may not yield an ideal buffered shape, making it impossible to calculate the theoretical and actual differences in the perimeter before and after buffering. Alternatively, the theoretical and actual differences may be similar, making it difficult to accurately identify even small elongated regions. Summary of the Invention

[0004] To address the technical problem of searching for small, narrow regions, this invention proposes a method, system, and storage medium for extracting narrow regions, achieved through the following technical solutions:

[0005] In a first aspect, this application provides a method for extracting elongated regions, characterized by comprising the following steps:

[0006] Acquire the graphic data to be processed;

[0007] Based on the graphic data to be processed, a closed surface formed by connecting several line segments is obtained;

[0008] Extract the first node and / or the last node of each line segment to generate line nodes;

[0009] Perform distance analysis on the line nodes to obtain the line segment that is closest to the line node within a preset range, wherein the line node that finds the closest line segment is marked as a face node;

[0010] Based on the face node and the nearest line segment, a connecting line is obtained, the length of which is the minimum distance between the face node and the corresponding nearest line segment.

[0011] Extract the line segments containing all the face nodes to generate line features;

[0012] Construct a plane based on the line element and the connecting line, and fuse to generate a fused plane after the plane is constructed.

[0013] By adopting the technical scheme, the processing of the closed graph to be processed is converted into analysis between the face edge line and the face node, the face edge line closest to the face node is found, the position closest between the point line and the connecting line is connected, the connecting line intersecting with the straight line segment where the face node is located is obtained, and the straight line segment and the connecting line are constructed after the plane is constructed and then fused. In this way, the search judgment and extraction of the long and narrow area are completed, which is relatively accurate, and the logic is simple and the efficiency is high.

[0014] Preferably, the step of performing distance analysis on the line node to obtain a straight line segment closest to the line node within a preset range specifically comprises:

[0015] determining whether there is a distance between the straight line segment and the line node greater than 0 and less than a preset distance value, if there is, the straight line segment is represented as the closest straight line segment;

[0016] determining whether the number of the closest straight line segment corresponding to each line node is greater than 1, if yes, the closest straight line segment with the smallest distance is left, and the remaining straight line segments are removed from the closest straight line segment.

[0017] By adopting the technical scheme, the closest straight line segment with a distance greater than 0 is found within a preset range first, and then screened, so that the closest straight line segment corresponding to each line node is unique, the data processing amount in the subsequent process is reduced, and the search efficiency is improved.

[0018] Preferably, after the step of extracting the straight line segment where all the face nodes are located, the following steps are included:

[0019] Based on the closed plane, the connecting line located outside the closed plane is removed.

[0020] In the process of finding the closest straight line segment and obtaining the connecting line, there may be a connecting line located outside the closed plane. The connecting line and the line element are mostly triangular and other graphics, and are not the required long and narrow area. Therefore, by adopting the technical scheme, the connecting line located outside the closed plane is removed, so as to avoid that the long and narrow plane originally does not exist exists in the long and narrow plane finally obtained, and affect the final search accuracy.

[0021] Preferably, after the step of constructing a plane and then fusing to generate a fused plane, the following steps are included:

[0022] determining whether the shape of all the fused planes is a triangle, if yes, the fused plane of the triangle is removed; if no, the fused plane is marked as a first fused plane.

[0023] By adopting the technical scheme, according to the definition of the narrow region, the width of the narrow face should be less than 0.1 meter, and the length is at least 20 times of the width, and the triangular face does not meet the condition, so the triangular fusion face needs to be removed.

[0024] Preferably, after the step of marking the fusion face as the first fusion face, the method comprises:

[0025] Obtaining angle data of all internal angles of the first fusion face;

[0026] Removing the internal angle with all the angle data less than 10°.

[0027] By adopting the technical scheme, in the process of searching for the narrow face, the sharp angle part of the obtained fusion face has a high probability of not belonging to the narrow face, and the part with a particularly small angle is basically located in a large graph and does not belong to the narrow face, so the angle that does not meet the requirement needs to be removed, thereby improving the accuracy of the extraction of the narrow face.

[0028] Preferably, after the step of removing the internal angle with all the angle data less than 10°, the method further comprises:

[0029] Judging whether the first fusion face still exists a triangle, if yes, removing the first fusion face of the triangle, and if no, keeping the first fusion face.

[0030] By adopting the technical scheme, after removing the sharp angle, the obtained fusion face can generate a new triangular fusion face, which affects the final search result. In order to avoid the influence on the subsequent extraction of the narrow region, it is necessary to search again whether there is a triangular fusion face, and to remove the found triangular fusion face, thereby further increasing the accuracy of the final search result.

[0031] Preferably, after the step of judging whether the first fusion face still exists a triangle, the method comprises:

[0032] Obtaining width data of the connecting line, and calculating a width mean value based on the width data of the same first fusion face;

[0033] Generating a center line of the first fusion face based on the line element and / or the connecting line, and calculating a line length of the center line;

[0034] Judging whether the line length of the same first fusion face is greater than 20 times of the width mean value, if no, removing the first fusion face.

[0035] By adopting the technical scheme, the length of the long and narrow face is usually 20 times or more than the width, the width of the first fusion face is unified, because the shape of the long and narrow face is not regular, the mean value of the length is difficult to obtain, and because the width is small, the accuracy is not high. In contrast, the center line is easy to obtain, and its mean value is close to the length, so the center line is used to replace the comparison, which reduces the difficulty of judgment and improves the accuracy and efficiency.

[0036] Preferably, the step of generating the center line of the first fusion face based on the line element and / or the connecting line specifically comprises:

[0037] Obtaining a boundary line of the first fusion face coinciding with the line element;

[0038] Based on the mean value of the width, one boundary line of the same first fusion face is divided into a plurality of sub-line segments with a length of the mean value of the width;

[0039] The plurality of sub-line segments are rotated by 90° in the direction of the first fusion face;

[0040] Connecting the midpoints of the plurality of sub-line segments located in the first fusion face to obtain the center line.

[0041] By adopting the technical scheme, the center line obtained in this way is used as the length of the long and narrow face, which is compared with the width of the long and narrow face, so that the result is more accurate, and a long and narrow face that conforms to the definition is obtained.

[0042] In a second aspect, the present application also provides a face long and narrow area extraction system, characterized in that it comprises a memory and a processor, the memory is used to store a computer program, and the processor executes the face long and narrow area extraction method according to any one of claims 1-8 according to the computer program.

[0043] By adopting the technical scheme, the memory can store information, the processor can retrieve and issue control instructions, ensure the orderly execution of the program and realize the effect of the above scheme.

[0044] In a third aspect, the present application also provides a computer readable storage medium, characterized in that the storage medium has at least one instruction, at least one program, a code set or an instruction set, and the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by the processor to execute the face long and narrow area extraction method according to any one of claims 1-8.

[0045] By adopting the technical scheme, when the computer readable storage medium is loaded into any computer, any computer can execute the face long and narrow area extraction method provided by the present application.

[0046] Compared with the prior art, the application has the following advantages and beneficial effects:

[0047] 1. By converting the processing of the entire closed surface into the analysis between the surface nodes and the surface edges, the position closest to the distance between the point line is connected by finding the straight line segment closest to the distance within the preset range and greater than 0, to obtain the connecting line intersecting the straight line segment where the surface node is located; and the straight line segment and the connecting line are fused after surface construction to obtain the fusion surface. The method simplifies the problem, the logic and process of searching are simpler, and the searching, calculation and processing are automatically performed by the computer program, without relying on manual operation, the data amount that can be processed is large, the data quality is improved, and the efficiency is high.

[0048] 2. The fusion surface obtained after surface construction is further processed, the triangular fusion surface and sharp corners are removed after judgment, and the fusion surface obtained by using the center line is judged to determine whether it meets the definition of the narrow region to complete the searching and determining of the narrow region, reduce the extraction error, and make the final result more accurate. BRIEF DESCRIPTION OF DRAWINGS

[0049] The accompanying drawings, which are included to provide a further understanding of the embodiments of the application and constitute a part of this application, illustrate embodiments of the application and do not limit the embodiments of the application. In the drawings:

[0050] Figure 1 is a flowchart of the embodiments of the application.

[0051] Figure 2 is a schematic view of the original closed surface split into several straight line segments.

[0052] Figure 3 is a flowchart of searching for the straight line segment closest to the distance.

[0053] Figure 4 is a schematic view of searching for the straight line segment closest to the distance.

[0054] Figure 5 is a schematic view of the fusion surface obtained after surface construction and fusion.

[0055] Figure 6 is a flowchart of processing the fusion surface.

[0056] Figure 7 is a flowchart of removing the sharp corners.

[0057] Figure 8 is a flowchart of obtaining the center line. DETAILED DESCRIPTION

[0058] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0059] The embodiments of the present invention will now be described in further detail with reference to the accompanying drawings.

[0060] This application provides a method for extracting elongated regions, such as... Figure 1 As shown, it includes the following steps:

[0061] Step S100: Obtain the graphic data to be processed.

[0062] Step S200: Based on the graphic data to be processed, obtain a closed surface formed by connecting several line segments.

[0063] After obtaining the graphic to be processed, the edges of the original surface features are densified to obtain closed surfaces composed of straight line segments. The densification distance is y, which can be manually adjusted according to the length of the original surface feature edges, ensuring that there is a node between the two lines in a narrow region. If there is no node between the two lines in a narrow region, a connecting line cannot be generated in the middle during subsequent searches, making it impossible to accurately locate the narrow region.

[0064] like Figure 2 As shown, after obtaining the closed surface from the graphic to be processed, the surface is divided into several straight line segments with two nodes, a first node and / or a tail node, according to the shape of the closed surface. The straight line segments are denoted as A and numbered, and each straight line segment is assigned a unique number.

[0065] Step S300: Extract the first node and / or the last node of each line segment to generate line nodes.

[0066] Here, the line node is labeled B. The number of B is the same as the unique number of the line segment. When taking the first and last nodes of the line segment, each endpoint of the line segment corresponds to two line nodes B, and the two line nodes B have different numbers.

[0067] Step S400: Perform distance analysis on the line nodes to obtain the line segments that are closest to the line nodes within a preset range. The line node that finds the closest line segment is marked as a surface node.

[0068] Furthermore, when performing distance analysis on line nodes to obtain the straight line segment closest to the line node within a preset range, such as... Figure 3 As shown, it includes the following steps:

[0069] Step S410: judging whether there is a straight line segment and a line node distance greater than 0, and less than a preset distance value, if so, the straight line segment is characterized as the nearest straight line segment;

[0070] Step S420: judging whether the number of the nearest straight line segment corresponding to each line node is greater than 1, if so, leaving the nearest straight line segment with the smallest distance, and eliminating the remaining straight line segments from the nearest straight line segment.

[0071] Through the technical solutions of steps S410-S420, the distance analysis is performed on the straight line segment in A and the line node in B, each line node finds the straight line segment with a distance greater than 0 and within a preset range, the line node finding the straight line segment meeting the requirements is marked as a face node, denoted as B', and the straight line segment meeting the requirements is characterized as the nearest straight line segment, wherein the preset range can be flexibly adjusted according to the definition of the gap.

[0072] In this process, in one case, there can be more than one nearest straight line segment corresponding to each face node, at this time, the length value of each nearest straight line segment corresponding to the face node is obtained, and after comparison and screening, the nearest straight line segment with the smallest distance is left, and the remaining nearest straight line segments are eliminated. The position coordinates of the point on the nearest straight line segment corresponding to the face node and closest to the face node are found and marked, for example, as shown in Figure 4 The straight line segment is numbered as A12, and the face node existing on the straight line segment is numbered as B'12. The first face node on the straight line segment A12 is analyzed, and the first face node is marked as C1, the first face node inherits the number of B' as C1-12, and the position coordinates of the first face node are marked as B'x1, B'y1. The number of the nearest straight line segment corresponding to the first face node C1-12 is A37, and the point on the straight line segment A37 corresponding to the first face node C1-12 and closest to the first face node is marked as C2, and the position coordinates of C2 are marked as B'x2, B'y2. In another case, there can be no straight line segment meeting the requirements, at this time, it is indicated that there is no long and narrow face in the region, and the subsequent searching step is stopped.

[0073] Step S500: obtaining a connecting line based on the face node and the nearest straight line segment, and the length of the connecting line is the minimum distance between the face node and the corresponding nearest straight line segment.

[0074] The connecting line of the face node and the corresponding nearest straight line segment is obtained and marked as D. For example, the first face node C1-12 and the corresponding nearest point C are connected to obtain the connecting line D, and the length of the connecting line D is the minimum distance between the first face node C1-12 and the corresponding nearest straight line segment A37.

[0075] Step S600: Extract all the straight line segments where the nodes are located to generate line elements.

[0076] Screen A with the number of B', keep the same number of straight line segments and mark as E. Among them, in order to ensure that the line elements found by numbering are not missing, the head node and tail node of the straight line segment are selected as line nodes B in step S300.

[0077] At the same time, according to the spatial relationship, compared with the original closed surface, the connecting line located outside the closed surface or partially located outside the closed surface is removed, and the connecting line in the closed surface is left and marked as F.

[0078] Step S700: Construct the surface based on the line elements and connecting lines, and fuse to generate the fused surface.

[0079] As shown in Figure 5 , the data is constructed and fused using E and F to obtain the fused surface.

[0080] After fusion, there may be some triangular fusion surfaces and / or sharp corners, which need to be removed. Further, after obtaining the fused surface, as shown in Figure 6 , the following steps are included:

[0081] Step S610: Determine whether the shape of all fused surfaces is triangular, if so, remove the triangular fused surface, if not, mark the fused surface as the first fused surface.

[0082] This step specifically acquires the point number data of each fused surface. If there is a fused surface with only four nodes, it is determined that the fused surface is a triangular fused surface, which needs to be removed. If the number of nodes in the fused surface is greater than four, the fused surface is retained, and the remaining fused surface after removing the triangular fused surface is marked as the first fused surface.

[0083] Among them, in the above triangular judgment, the number of nodes can also be three. Whether four or three nodes are used for judgment mainly depends on the judgment of the system for graph generation. If the head node and tail node with the same position coordinates of the triangle are regarded as two nodes, four nodes are used for judgment, otherwise three nodes are used for judgment.

[0084] Step S620: Acquire the angle data of all the internal angles of the first fused surface; remove the internal angles with all angle data less than 10°.

[0085] The internal angle area removed in this way is the triangular area formed by two connecting lines and a line element where the internal angle is located.

[0086] Specifically, as shown in Figure 7As shown, in one embodiment, the inner angle removal includes the following steps:

[0087] S621: Obtain the face node where the vertex of the inner angle with an angle data less than 10° is located, and the connecting line and line element constituting the inner angle.

[0088] S622: Obtain the other face node of the connecting line and line element constituting the inner angle, which is not the vertex of the inner angle.

[0089] Remove the connecting line and line element.

[0090] S623: Connect the other face node of the connecting line and line element constituting the inner angle, which is not the vertex of the inner angle, to obtain a new connecting line, which is the new boundary line of the first fusion surface.

[0091] Step S630: Determine whether there is a triangle in the first fusion surface after removing the inner angle with an angle data less than 10°. If yes, remove the first fusion surface of the triangle; if no, keep the first fusion surface.

[0092] After removing the sharp angle, a new triangle fusion surface may be generated in the first fusion surface, so it is necessary to determine again whether there is a triangle in the fusion surface after removing the sharp angle. The specific implementation of this step is the same as that of step S610.

[0093] Step S640: Obtain the width data of the connecting line, and calculate the average width based on the width data of the same first fusion surface.

[0094] Step S650: Generate the center line of the first fusion surface based on the line element and / or the connecting line, and calculate the line length of the center line.

[0095] According to the straight line segment E and the connecting line F, the center line of the fusion surface is generated and the line length of the center line is calculated. The step of generating the center line includes the following steps as shown: Figure 8

[0096] Step S651: Obtain the line boundary line coinciding with the line element of the first fusion surface.

[0097] Step S652: Based on the average width, divide one boundary line of the same first fusion surface into a plurality of sub-line segments with an average width length.

[0098] Step S653: Rotate the plurality of sub-line segments by 90° in the direction of the interior of the first fusion surface.

[0099] Step S654: Connect the midpoints of the plurality of sub-line segments located in the first fusion surface to obtain the center line.

[0100] ​Because the obtained fusion surface can not be a regular graph, and the width is not uniform, the calculated average width is taken as the width of the fusion surface, and the width value of the fusion surface is unified.

[0101] Step S660: determining whether the line length of the same first fusion surface is greater than 20 times the average width, and if not, the first fusion surface is removed.

[0102] The line length of the center line is compared with 20 times the unified width value. If the line length of the center line is greater than 20 times the unified width value, the obtained fusion surface is determined to be a final narrow surface that meets the requirements. If not, the fusion surface is removed.

[0103] In other embodiments of the present application, the half of the total length of the straight line segments other than the connecting line of the obtained narrow surface can also be compared with 20 times the unified width value. This method has slightly lower accuracy than using the center line, but the method of obtaining the total length of the straight line segments other than the connecting line of the narrow surface is simpler than the center line, and the comparison is more convenient and easy to implement.

[0104] The present application also provides a surface narrow area extraction system, comprising a data acquisition module, a surface acquisition module, a node extraction module, a data analysis module, a data processing module, and a data execution module. Among them,

[0105] The data acquisition module is used to acquire the to-be-processed graphic data;

[0106] The surface acquisition module is used to obtain a closed surface formed by connecting a plurality of straight line segments based on the to-be-processed graphic data;

[0107] The node extraction module is used to extract the head node and / or tail node of each straight line segment to generate a line node;

[0108] The data analysis module is used to perform distance analysis on the line node to obtain a straight line segment closest to the line node within a preset range, wherein the line node that finds the closest straight line segment is marked as a surface node;

[0109] The data processing module is used to obtain a connecting line based on the surface node and the closest straight line segment, wherein the length of the connecting line is the minimum distance between the surface node and the corresponding closest straight line segment; and extract the straight line segment where all the surface nodes are located to generate a line element;

[0110] The data execution module is used to construct a surface based on the line element and the connecting line, and to generate a fusion surface after the surface is constructed.

[0111] The application further provides a computer readable storage medium, which has at least one instruction, at least one program, a code set or an instruction set, and the at least one instruction, the at least one program, the code set or the instruction set are loaded and executed by a processor to realize the face and long area extraction method.

[0112] The above merely provides the preferred embodiment of the present application, but should not be used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for extracting a face from a long and narrow region, characterized by, The method comprises the following steps: acquiring to-be-processed graphic data; obtaining a closed surface formed by connecting a plurality of straight line segments based on the to-be-processed graphic data; extracting a head node and / or a tail node of each straight line segment to generate a line node; performing distance analysis on the line node to obtain a straight line segment closest to the line node within a preset range, wherein the line node that finds the straight line segment closest to the line node is marked as a surface node; obtaining a connecting line based on the surface node and the closest straight line segment, wherein the length of the connecting line is the minimum distance between the surface node and the corresponding closest straight line segment; and extracting a straight line segment on which all the surface nodes are located to generate a line element; constructing a surface based on the line element and the connecting line, and fusing to generate a fused surface after the surface is constructed; the step of performing distance analysis on the line node to obtain a straight line segment closest to the line node within a preset range specifically comprises: judging whether there is a straight line segment whose distance to the line node is greater than 0 and less than a preset distance value, and if so, regarding the straight line segment as the closest straight line segment; judging whether the number of the closest straight line segments corresponding to each line node is greater than 1, and if so, leaving the closest straight line segment with the minimum distance and eliminating the remaining straight line segments from the closest straight line segments; after the step of fusing to generate a fused surface after the surface is constructed, the following steps are included: judging whether the shape of all the fused surfaces includes a triangle, and if so, removing the fused surface of the triangle; and if not, marking the fused surface as a first fused surface; after the step of marking the fused surface as a first fused surface, the following steps are included: acquiring angle data of all internal angles of the first fused surface; removing internal angles with all the angle data less than 10°; after the step of removing internal angles with all the angle data less than 10°, the following steps are included: judging whether the first fused surface still includes a triangle, and if so, removing the first fused surface of the triangle; and if not, keeping the first fused surface; after the step of judging whether the first fused surface still includes a triangle, the following steps are included: acquiring width data of the connecting line, and calculating a width average value based on the width data of the same first fused surface; generating a center line of the first fused surface based on the line element and / or the connecting line, and calculating a line length of the center line; judging whether the line length of the same first fused surface is greater than 20 times of the width average value, and if not, eliminating the first fused surface.

2. The method of claim 1, wherein, after the step of extracting a straight line segment on which all the surface nodes are located, the following steps are included: eliminating the straight line segment located outside the closed surface based on the closed surface.

3. The method of claim 1, wherein, the step of generating a center line of the first fused surface based on the line element and / or the connecting line specifically comprises: generating a boundary line by overlapping the first fused surface and the line element; dividing one boundary line of the same first fused surface into a plurality of sub-line segments with a length of the width average value based on the width average value; rotating the plurality of sub-line segments by 90° in the direction of the inside of the first fused surface; connecting the midpoints of the plurality of sub-line segments located in the first fused surface to obtain the center line.

4. A face long area extraction system characterized by, The system for performing the method for extracting a planar long region according to any one of claims 1-3 comprises a data acquisition module, a plane acquisition module, a node extraction module, a data analysis module, a data processing module, and a data execution module. The data acquisition module is configured to acquire to-be-processed graphic data. The plane acquisition module is configured to obtain a closed plane formed by connecting a plurality of straight line segments based on the to-be-processed graphic data. The node extraction module is configured to extract a head node and / or a tail node of each straight line segment to generate a line node. The data analysis module is configured to perform distance analysis on the line node to acquire a straight line segment closest to the line node within a preset range, wherein the line node that finds the straight line segment closest to the line node is marked as a plane node. The data processing module is configured to obtain a connecting line based on the plane node and the closest straight line segment, wherein the length of the connecting line is the minimum distance between the plane node and the corresponding closest straight line segment; and extract a straight line segment on which all the plane nodes are located to generate a line feature. The data execution module is configured to construct a plane based on the line feature and the connecting line, and fuse to generate a fused plane after the plane is constructed.

5. A computer readable storage medium, characterized in that, The storage medium has at least one instruction, at least one program, a code set, or an instruction set, and the at least one instruction, the at least one program, the code set, or the instruction set is loaded by a processor and performs the method for extracting a planar long region according to any one of claims 1-3.

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