Special-shaped pattern spot processing method suitable for forest grass ecological comprehensive monitoring pattern spot investigation

Abstract

The invention relates to the technical field of special-shaped pattern spot processing, and particularly discloses a special-shaped pattern spot processing method suitable for forest grass ecological comprehensive monitoring pattern spot investigation, and the method comprises the following steps: carrying out the closed operation of an original pattern spot; calculating a perimeter theoretical difference value before and after closed operation; calculating the actual difference value of the perimeters before and after operation; judging local long and narrow pattern spots; cutting a sharp angle pattern spot; compared with a traditional manual processing method or a simple general image processing method, the method has the advantages that a large number of special-shaped image spots can be processed in a shorter time, the requirement of a large-scale forest and grass ecological comprehensive monitoring project for data processing timeliness is met, and the method is suitable for large-scale forest and grass ecological comprehensive monitoring. And a guarantee is provided for timely mastering dynamic conditions of ecological systems of forests, grasslands, wetlands and deserts.

Description

Technical Field

[0001] The present invention belongs to the technical field of processing irregular-shaped spots, and in particular relates to a method for processing irregular-shaped spots suitable for surveying forest and grassland ecological comprehensive monitoring spots. Background Art

[0002] Since the forest, grassland, wetland and wasteland data and the third national land survey data were not under the same jurisdiction in the original survey, there were differences in the scope judgment of individual spots during the internal delineation, resulting in a large number of narrow and sharp small spots in the data fusion process. If these spots are processed manually, the efficiency is very low. Therefore, it is urgent to find a method to quickly identify and process such spots.

[0003] Traditional data processing simplification methods include: Douglas-Peucker algorithm, Li-Openshaw algorithm, skeleton line merging algorithm based on Delaunay triangulation constraints, etc. However, these methods have two obvious drawbacks:

[0004] First, it can identify the protruding or narrow areas of regular spots, but it cannot correctly identify special narrow spots. Regarding narrow spots, the industry in the field of cartographic synthesis generally uses the shape index to judge: the ratio of area divided by perimeter is less than 0.2 for narrow spots. This judgment method is very effective for spots with a narrow shape as a whole, but if the spot is not narrow as a whole, but only has a thin "tail" in a local area, this method cannot handle it.

[0005] Second, when processing sharp spots, it is easy to produce topological errors such as self-intersection due to excessive curvature or unreasonable threshold setting, which reduces data quality. The Douglas-Peucker algorithm or Li-Openshaw algorithm requires setting a reasonable comprehensive threshold or SVO (minimum visible object) parameter. If the parameter is set too large, topological errors will occur during data processing; if the parameter is set too small, it is often difficult to eliminate sharp shapes. It is difficult to ensure the accuracy and reliability of multi-source heterogeneous data fusion. Summary of the invention

[0006] The purpose of the present invention is to provide a method for processing irregular patches suitable for forest and grassland ecological comprehensive monitoring patch surveys, so as to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for processing irregular-shaped spots suitable for forest and grassland ecological comprehensive monitoring spot survey comprises the following steps:

[0009] S1, perform closing operation on the original image patch;

[0010] S2, calculate the theoretical difference of the perimeter before and after the closing operation;

[0011] S3, calculating the actual difference in circumference before and after the operation;

[0012] S4, determining the local narrow and long spots;

[0013] S5, sharp angle pattern cutting;

[0014] S6: small image spots are merged and processed.

[0015] Preferably, the specific steps of the S1 closing operation are: using the closing operation in the expansion and corrosion theory to close the original spot S 1 Buffer inward to form a new image spot S 2 , providing basic data for the subsequent calculation of perimeter difference and determination of pattern characteristics.

[0016] Preferably, the theoretical difference of the perimeter before and after the closing operation is calculated in S2

[0017] Difference formula:

[0018] S(p,r)=6.4r*5=32r.

[0019] Preferably, in the actual difference in circumference before and after the S3 calculation operation, the circumference calculation tool of the independently developed Qilin Forest, Grassland and Wetland Survey System software is used to calculate the circumference of the original figure and the figure after the closed operation, and the difference is obtained to obtain S', which is compared with the theoretical circumference value S. The actual calculated difference is compared with the theoretical threshold value to determine whether the pattern is a local narrow and long pattern.

[0020] Preferably, in the S4, if S'-S>32r, the local narrow and long spots are identified as local narrow and long spots; otherwise, if S'-S<32r, it is considered not to be a local narrow and long spot, and the local narrow and long spots required are screened out.

[0021] Preferably, in the S5 sharp-angle spot cutting, the identified local narrow and long spots are quantitatively set with a closed operation to perform sharp-angle cutting on the buffer angle adaptation and extension parameters.

[0022] Preferably, in the S6 small patch merging process, the "thin seam" patches produced by cutting are merged into adjacent patches based on a comprehensive judgment of the maximum shared edge length and the semantic attributes of forest and grass.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] By performing a series of operations such as closing the original spots, accurately calculating the perimeter difference, and determining narrow and long spots, it is possible to effectively identify and process irregular spots. The processed spots have significantly improved the measurement accuracy of perimeter and area. Compared with traditional unprocessed data, the perimeter measurement error can be reduced, and the area measurement error can be reduced, thereby providing a more reliable basis for subsequent survey and monitoring data analysis, ensuring that the monitoring results can truly reflect the actual situation of forest and grass resources and ecology. At the same time, sharp angle cutting and small spot merging processing effectively improve the geometric shape of the spots. The integrity and coherence of the spot data are enhanced. In the work of defining the boundaries of forest and grass ecosystems and dividing ecological types, the processed spots can more clearly present the scope and characteristics of different ecological regions, improving the efficiency of ecosystem research and management.

[0025] The present invention designs methods based on the actual situation of forest and grassland resources. For example, the vegetation growth law and terrain characteristics are fully considered in terms of buffer radius setting, buffer angle adaptability and extension parameter selection. This makes the processed map data more in line with the actual management of forest and grassland resources, and has stronger practicality in the monitoring of map land type changes and the formulation of ecological protection plans. Compared with traditional manual processing or simple general image processing methods, the present invention can complete the processing of a large number of special-shaped maps in a shorter time, meet the requirements of large-scale comprehensive forest and grassland ecological monitoring projects for data processing timeliness, and provide basic support for timely grasp of the dynamic changes of forest and grassland resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the process of the heterogeneous pattern processing technology based on the stepping technology of the present invention;

[0027] Figure 2 It is a schematic diagram of the processing flow of local narrow and long spots of the present invention. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Embodiment 1:

[0030] In the comprehensive monitoring of forest and grassland ecology, the accuracy and rationality of the patch data are crucial. The existence of irregular patches will affect the reliability of the survey and monitoring results, as well as the convenience of forest and grassland resource management, so effective processing methods are needed.

[0031] The original patch data of the area was extracted from the forest and grassland ecological comprehensive monitoring database. The patch numbered [TP001] had an irregular shape and was suspected to have narrow and long parts and sharp corners. It was taken as the target patch for this processing, and the buffer radius r was set to 6 meters.

[0032] Closing operation and theoretical difference calculation

[0033] Using the closing operation function in the Qilin forest, grassland and wetland survey system, the map TP001 is buffered inward to generate a new map TP001. s 2.

[0034] The theoretical difference is calculated according to the formula:

[0035] First, according to the original theoretical formula

[0036]

[0037] Calculation, since the number of vertices of the pattern is p = 18, but because the calculation of angles is complicated, the improved formula is simplified by assuming that all internal angles are approximately equal;

[0038]

[0039] Calculate, we can get

[0040]

[0041] S theoretically about 38.44 meters

[0042] Refer to the simplified general formula obtained by stepping technique:

[0043] S improvement (p, r) = 6.4r

[0044] The following formula is obtained by adjusting according to the actual situation:

[0045] S(p,r)=6.4r*5=32r

[0046] The calculated result is 192 meters.

[0047] Actual difference calculation and narrow and long spot determination

[0048] Using the perimeter calculation tool of the Qilin Forest Grassland Wetland Survey System, the perimeter C of the original spot TP001 was measured. 原 = 800 meters, after the closing operation, the perimeter of the spot TP001s2 is C 闭 = 350 meters, actual circumference difference S' = C 原 -C 闭＝ 450 meters, because S'-S=450-192=258 meters is greater than 32r=32x6=192 meters, so the pattern TP001 is determined to be a local narrow and long pattern.

[0049] Sharp corner cutting and small spot merging

[0050] For the sharp corners of the TP001 patch, the closed operation was used in the Qilin Forest and Grassland Survey System, and the buffer angle adaptation was set to 30° (determined according to the patch shape characteristics and the needs of forest and grass resource management to ensure that the cutting does not affect the management and can improve the shape), and the extension parameter was 2 meters (adjusting the patch boundary within a reasonable range to avoid excessive cutting) for sharp corner cutting. After cutting, the patch shape was significantly improved and the irregularity was reduced. After cutting, some small "slit" patches were generated, such as [TP001 f1] and [TP001_f2]. By analyzing the maximum shared edge length with the adjacent patches, it was found that [TP001_f1] shared the longest edge length with the adjacent patch [TP002], and the semantic attributes of both patches were grassland types, which met the merging conditions, and [TP001f11] was merged into TP002; similarly, other small patches were processed similarly, and finally the small patches were merged, making the patch boundary layout more reasonable, which was convenient for subsequent resource statistical analysis and management.

[0051] In summary, after the above-mentioned special-shaped patch processing process, the shape of the patch and its related small patches are optimized, and the accuracy and rationality of the patch data are significantly improved. The processed patch data can more accurately reflect the resource status and ecological status of the region in the subsequent comprehensive monitoring and analysis of forest and grassland ecology, such as more accurate statistics on vegetation coverage and clearer definition of ecosystem boundaries, providing strong support for scientific ecological protection and management decisions.

[0052] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0053] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for processing irregular spots suitable for forest and grassland ecological comprehensive monitoring spot survey, characterized in that: The following steps are involved: S1, perform closing operation on the original image patch; S2, calculate the theoretical difference of the perimeter before and after the closing operation; S3, calculating the actual difference in circumference before and after the operation; S4, determining the local narrow and long spots; S5, sharp angle pattern cutting; S6: small image spots are merged and processed.

2. The method for processing irregular spots suitable for forest and grassland ecological comprehensive monitoring spot survey according to claim 1 is characterized by: The specific steps of the S1 closing operation are: using the closing operation in the expansion and corrosion theory to buffer the original spot S1 inward to form a new spot S2, providing basic data for subsequent calculation of the perimeter difference and determination of the spot characteristics.

3. The method for processing irregular spots suitable for forest and grassland ecological comprehensive monitoring spot survey according to claim 1 is characterized by: In S2, the theoretical difference of the perimeter before and after the closing operation is calculated. Difference formula: S(p,r)=6.4r*5=32r.

4. The method for processing irregular spots suitable for forest and grassland ecological comprehensive monitoring spot survey according to claim 1 is characterized by: In the S3 calculation of the actual difference in perimeter before and after the operation, the Qilin Forest, Grassland and Wetland Survey System calculation tool is used to calculate the perimeters of the original figure and the figure after the closed operation, and the difference is obtained to obtain S', which is compared with the theoretical perimeter value S. The actual calculated difference is compared with the theoretical threshold to determine whether the pattern is a local narrow and long pattern.

5. The method for processing irregular spots suitable for forest and grassland ecological comprehensive monitoring spot survey according to claim 1 is characterized by: In the above S4, if S'-S>32r, the local narrow and long spots are identified as local narrow and long spots; otherwise, if S'-S<32r, it is considered not to be a local narrow and long spot, and the local narrow and long spots required are screened out.

6. The method for processing irregular spots suitable for forest and grassland ecological comprehensive monitoring spot survey according to claim 1 is characterized by: In the S5 sharp-angle spot cutting, the identified local narrow and long spots are quantitatively set with closed operations to perform sharp-angle cutting with buffer angle adaptation and extension parameters.

7. The method for processing irregular spots suitable for forest and grassland ecological comprehensive monitoring spot survey according to claim 1 is characterized by: In the S6 small patch merging process, the "thin crack" patches produced by cutting are merged into adjacent patches based on a comprehensive judgment of the maximum shared edge length and the semantic attributes of forest and grass.

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