Non-resident island resource monitoring method based on spatial three-dimensional model

Abstract

The invention relates to the technical field of ecological monitoring, in particular to a resident-free island resource monitoring method based on a spatial three-dimensional model, and the method comprises the following steps: S1, building a remote sensing image interpretation information base; s2, based on the remote sensing image interpretation information base, generating an island space three-dimensional model containing island land terrain and shoreline distribution; s3, generating a total element three-dimensional dynamic map; s4, the interpretation result and the total element three-dimensional dynamic map in the S3 are superposed, and a reef area comprehensive distribution map is generated; s5, calculating the island resource development intensity and the ecological risk level, and outputting an island ecological assessment report; and S6, generating an island resource monitoring report. According to the invention, unmanned aerial vehicle aerial survey, GNSS measurement, depth sounding technology, image interpretation and ecological assessment are combined, a high-precision total-factor three-dimensional dynamic monitoring system is constructed, accurate analysis and visual expression of the current island resource utilization situation are realized, and scientific decision support is provided for island management and ecological protection.

Description

Technical Field

[0001] This invention relates to the field of ecological monitoring technology, and in particular to a method for monitoring resources of uninhabited islands based on a spatial three-dimensional model. Background Technology

[0002] With the increasing demand for marine resource development and ecological protection, the monitoring and management of uninhabited islands has received growing attention. Factors such as the dynamic changes in island coastlines, the evolution of underwater topography, the development and utilization of reef areas, and the stability of the ecological environment directly affect the sustainable development and ecological security of islands. Currently, monitoring island resources using remote sensing, surveying, and ecological assessment models has become a research hotspot. While traditional remote sensing image analysis methods can obtain geographic information about islands, the lack of detailed topographic data makes it difficult to fully reflect the three-dimensional geomorphological characteristics of the islands. Furthermore, existing marine surveying methods mainly rely on individual depth measurements or coastline surveys, lacking comprehensive land-underwater integrated data fusion technology. This results in monitoring results that are difficult to represent in a spatially continuous and dynamically visualized manner, affecting the management department's accurate understanding and effective decision-making regarding island resource conditions.

[0003] Existing technologies have many limitations in monitoring uninhabited island resources, mainly in the following aspects: First, during the interpretation of remote sensing images, the extraction accuracy of information on shoreline type, topographic features, and development activities is low, making it difficult to support the needs of refined management; Second, underwater topographic data and island topographic data are difficult to integrate, resulting in a lack of integrity in the monitoring model and an inability to fully represent the three-dimensional spatial pattern of the island; Third, during the ecological assessment process, it is difficult to accurately calculate the intensity of island resource development and the level of ecological risk, resulting in a lack of scientific basis for monitoring results and an inability to provide effective management decision support. Summary of the Invention

[0004] To achieve the above objectives, this invention provides a method for monitoring resources on uninhabited islands based on a spatial three-dimensional model.

[0005] A method for monitoring resources on uninhabited islands based on a spatial three-dimensional model includes the following steps: S1: Obtain orthophoto data of the target island through UAV aerial survey, and combine it with historical remote sensing images and coastline mapping data to establish a remote sensing image interpretation database containing information on island coastline type, terrain features and development activities; S2: Based on the remote sensing image interpretation information database, the island coastline is measured in the field using the GNSS measurement system to obtain coastline inflection points, type boundary points and erosion zone characteristic data, and a three-dimensional spatial model of the island containing the island topography and coastline distribution is generated using three-dimensional modeling software. S3: Conduct water depth measurements in the waters surrounding the island to obtain underwater topographic data, and then integrate the underwater topographic data with the three-dimensional spatial model of the island in S2 to generate a full-element three-dimensional dynamic map that includes the island, coastline, and underwater topography. S4: Conduct UAV aerial surveys of the island and reef areas during low tide to obtain orthophotos of the reef distribution. Extract reef boundaries and development and utilization information through image interpretation technology. Overlay the interpretation results with the full-element 3D dynamic map of S3 to generate a comprehensive distribution map of the reef area. S5: Input the full-element three-dimensional dynamic map, the comprehensive distribution map of the reef area and ecological parameters into the ecological assessment model. By integrating shoreline stability, water depth change and biodiversity data, calculate the island resource development intensity and ecological risk level, and output the island ecological assessment report. S6: Based on the island ecological assessment report, generate a 3D visualization scene, a heat map of reef development and utilization, and an island resource monitoring report.

[0006] Optionally, S1 specifically includes: S11: Plan the drone aerial survey route within the target island area, set the flight altitude, flight path overlap rate and ground resolution, and use a multi-rotor drone equipped with a high-resolution RGB camera to take aerial photos along the set route to obtain high-definition image data covering the entire area of ​​the target island. S12: Perform image quality checks on the high-definition image data obtained in S11, use aerial triangulation to perform image stitching and orthorectification, and generate orthorectified image data of the target island area. S13: Acquire historical remote sensing image data and coastline mapping data of the target island, and preprocess the remote sensing images, including radiometric correction, geometric correction and image enhancement. S14: Using a human-computer interactive interpretation method, based on the orthophoto data generated in S12, the historical remote sensing image data and shoreline mapping data processed in S13 are overlaid to extract the target island's shoreline type information, terrain feature information and development activity area information, respectively. S15: Based on the shoreline type information, terrain feature information, and development activity area information interpreted in S14, integrate and classify the data according to geospatial location, and establish a target island remote sensing image interpretation information database composed of vector data and attribute data.

[0007] Optionally, S2 specifically includes: S21: Based on the shoreline distribution information in the remote sensing image interpretation database established in S1, a GNSS reference station is set up on the shoreline of the target island. The GNSS rover is used to conduct on-site reconnaissance and measurement along the shoreline location marked in the interpretation database to obtain the shoreline location information. S22: During the field measurement in S21, the GNSS measurement system was used to determine the coordinates of the inflection points at the locations of changes in the island's coastline morphology, and the coordinates of the type boundary points were measured at the locations where the coastline landform types changed. The characteristic locations of severely eroded areas were measured to obtain the coordinates and landform feature data of the eroded areas. S23: Based on the field coordinate data obtained from measurements in S21 and S22, and combined with the remote sensing image interpretation information database established in S1, the field measurement data and remote sensing image data are spatially matched using 3D geographic information system software, and a high-precision digital terrain model of the island is established through spatial interpolation. S24: Import the island digital terrain model established in S23 with the shoreline inflection points, shoreline type boundary points and erosion zone feature data obtained on site into the 3D modeling software ContextCapture. Based on the oblique photogrammetry 3D reconstruction method, perform spatial data fusion modeling to generate a target island spatial 3D model with real spatial location.

[0008] Optionally, S23 specifically includes: S231: Perform coordinate transformation on the GNSS field measurement coordinate data and elevation data obtained in S21 and S22, and unify them to the same geographic coordinate system as the remote sensing image interpretation information database established in S1. S232: Import the unified coordinate and elevation data from S231 into the 3D geographic information system software, use the Delaunay triangulation algorithm to generate an irregular triangular network, and establish the basic triangular surface data structure. S233: For the data points in the remaining uncovered areas of the irregular triangular network generated in S232, the elevation is calculated using inverse distance-weighted interpolation. The interpolation formula is: ,in, Here is the elevation value of the point to be interpolated. Let be the elevation value of the i-th known measurement point. is the planar distance between the point to be interpolated and the i-th known measurement point, and p is the exponent; S234: After interpolation is completed in S233, the interpolation result is overlaid with the orthophoto data obtained in S1 using 3D geographic information system software. The elevation and image are then fused according to the geographic coordinates to generate a digital terrain model of the island.

[0009] Optionally, S24 specifically includes: S241: Import the island digital terrain model generated in S233, the orthophoto data obtained in S1, and the reef area data obtained in S14 into the 3D modeling software ContextCapture to ensure the spatial consistency of each data within the same geographic coordinate system. S242: The imported orthophoto data is reconstructed using oblique photogrammetry 3D reconstruction technology. Local feature matching algorithm is used to extract feature points of each image to form a set of matching points. S243: Based on the set of matching points, determine the external orientation elements of each image using the principle of collinearity; S244: After determining the external orientation elements of each image, multi-view stereo matching technology is used to reconstruct dense point clouds of the matching point set to generate three-dimensional point cloud data of the target island; then, a mesh construction algorithm is used to construct a triangular mesh of the three-dimensional point cloud, and combined with texture mapping technology, orthophoto data and reef area data are superimposed on the mesh surface to complete spatial data fusion modeling and generate a three-dimensional spatial model of the target island with a real spatial location.

[0010] Optionally, S3 specifically includes: S31: Use a single-beam echo sounder to acquire underwater topographic data of the sea area surrounding the target island, record the coordinates of the start and end points of the survey line and the water depth value, and unify the obtained data into the same coordinate system as the three-dimensional spatial model of the island generated in S2; S32: The underwater topographic data obtained in S31 is imported into the 3D geographic information system software and overlaid with the 3D spatial model of the island generated in S2. The coordinate matching and geometric alignment of the island land topography and the sea water depth distribution are performed to ensure the seamless connection between the island land boundary and the underwater topography. S33: Use spatial interpolation methods to grid the discrete measurement points of underwater topographic data, interpolate the seabed elevation values ​​of uncovered areas, and fuse the resulting underwater digital topographic model with the island and land digital topographic model to form a unified three-dimensional dataset of island, land and underwater. S34: Import the 3D dataset obtained after fusion in step S33 into 3D modeling software, perform topology checks and surface stitching on the underwater terrain mesh and the island and land terrain mesh, and overlay the shoreline distribution information retained in S2 to generate a full-element 3D dynamic map that includes islands, land, shoreline and underwater terrain.

[0011] Optionally, S4 specifically includes: S41: During low tide, use drones to conduct aerial surveys of the target island reef area and obtain high-definition aerial images covering the reef area according to the planned flight route; S42: Import the high-definition aerial images acquired in S41 into the image processing software, perform relative and absolute orientation corrections, generate orthophoto data of the reef area using aerial triangulation, and use the same coordinate system to maintain consistency with the full-element three-dimensional dynamic map obtained in S3. S43: Apply image interpretation technology to extract features from the orthophoto data obtained in step S42, identify the boundary of the reef area based on the classification method of spectral features and texture features, and mark the development and utilization areas on the reef in combination with historical development data to obtain the boundary information and development and utilization information of the reef area. S44: Load the reef area boundary information and development and utilization information obtained in S43 into the full-element three-dimensional dynamic map environment of S3, and use coordinate overlay and spatial matching functions to fuse the reef area data with the island, land and underwater topography to form a complete comprehensive distribution map of the reef area.

[0012] Optionally, S43 specifically includes: S431: Perform spectral analysis on the orthophoto data acquired in S42, extract multispectral band data from the image, and calculate the Normalized Difference Water Index (NDWI) for the reef area; when the NDWI value is greater than a set threshold... When the NDWI value is below a certain level, the area is identified as a body of water; when the NDWI value is below a certain level... and above the threshold At that time, the area was identified as a reef area; S432: Perform texture feature analysis on the image region identified as a reef area in S431, calculate the Local Binary Pattern (LBP) value; and compare the calculated LBP value of the reef area with a threshold. Compare the values; if the LBP value is greater than... If the condition is met, the area is determined to be a rough reef area; otherwise, it is determined to be a smooth reef area. S433: Combine historical development data to obtain developed and utilized areas in historical remote sensing images, and calculate the Development Change Index (DCI) using a time-series change detection method; when the DCI exceeds a set threshold... If the area is deemed a newly developed area, it will be classified as such; otherwise, it will remain in its original development and utilization status. S434: Combining the reef area boundary information, reef surface roughness classification information, and development and utilization area information calculated by S431, S432, and S433, construct the reef area interpretation layer, perform geometric vectorization processing, and finally output the reef area boundary information and development and utilization information.

[0013] Optionally, S5 specifically includes: S51: Obtain the full-element 3D dynamic map of S3, the comprehensive distribution map of the reef area of ​​S4, and the ecological parameter data from the island's historical ecological monitoring database, and load the above data into the same ecological assessment model platform to achieve unified management of the island's overall topography, coastline, reef area, and ecological parameters. S52: In the ecological assessment model platform, the island resource development intensity is calculated based on the ratio between the developed land area within the island and the total island area, and is denoted as D; when D exceeds a predetermined threshold, it is rated as a high-intensity development area, otherwise it is rated as a low-intensity development area. S53: Combining the boundary information of ecologically sensitive areas extracted from the comprehensive distribution map of reef areas, and the biodiversity indicators and environmental pressure indicators in the island's historical ecological monitoring database, establish an ecological risk comprehensive evaluation model to comprehensively calculate the island's ecological risk level and record it as U; when U exceeds the set threshold, it is judged as a high ecological risk level, otherwise it is judged as a low ecological risk level. S54: The calculation results of S52 and S53 are combined with the results of the shoreline stability analysis to form an island ecological assessment report, which lists the island resource development intensity level, ecological risk level and shoreline stability status, and marks the geographical location and management points of high-risk areas.

[0014] Optionally, S6 specifically includes: S61: Based on a 3D geographic information system platform, the information on high-risk areas and resource development intensity levels in the island ecological assessment report is visualized and overlaid onto a full-element 3D dynamic map to generate a 3D visualization scene with interactive functions. S63: Based on the statistical results of reef development and utilization in the assessment report, and combined with the comprehensive distribution map of the reef area, the land use of the existing, under construction and potential development areas on the reef is weighted and allocated. The spatial analysis function of the geographic information system is used to generate a heat map of reef development and utilization, which intuitively reflects the distribution and density of development hotspots. S64: Based on 3D visualization scenes and heat maps of reef development and utilization, summarize indicators of ecological risk level, distribution of high-risk areas and resource protection needs, and compile island resource monitoring reports, including the overall resource status of the island, the current status of shoreline and reef area development and utilization, distribution of ecologically sensitive areas, management measures and recommendations.

[0015] The beneficial effects of this invention are: This invention combines UAV aerial surveying, GNSS measurement, and single-beam bathymetry to accurately acquire orthophotos, coastline distribution, and underwater topographic data of islands. Based on Delaunay triangulation and inverse distance weighted interpolation, it generates a high-precision digital terrain model of the islands. Furthermore, it utilizes oblique photogrammetry 3D reconstruction, combined with multi-view stereo matching and texture mapping techniques, to achieve high-precision fusion of island spatial data. This ensures the spatial integrity and refined representation of the monitoring model, thereby comprehensively reflecting the island's topographic features and improving monitoring accuracy and data consistency.

[0016] This invention extracts information on the boundaries and development of reef areas using image interpretation technology, and combines it with an ecological assessment model to calculate the intensity of island resource development and the level of ecological risk. This results in a monitoring report that includes a 3D visualization scene, a heat map of reef development and utilization, and a resource monitoring report. Through the fusion analysis of multi-source data, it can intuitively display the current status of island resource utilization and ecological change trends, providing island management departments with a scientific and accurate basis for decision-making. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the uninhabited island resource monitoring method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the method for generating a three-dimensional spatial model of an island according to an embodiment of the present invention. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should also be noted that, to make the embodiments more comprehensive, the following embodiments are the best and preferred embodiments, and those skilled in the art can use other alternative methods to implement some well-known technologies; moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0020] like Figures 1-2 As shown, a method for monitoring resources on uninhabited islands based on a spatial three-dimensional model includes the following steps: S1: Obtain orthophoto data of the target island through UAV aerial survey, and combine it with historical remote sensing images and coastline mapping data to establish a remote sensing image interpretation database containing information on island coastline type, terrain features and development activities; S2: Based on the remote sensing image interpretation information database, the island coastline is measured in the field using the GNSS measurement system to obtain coastline inflection points, type boundary points and erosion zone characteristic data, and a three-dimensional spatial model of the island containing the island topography and coastline distribution is generated using three-dimensional modeling software. S3: Conduct water depth measurements in the waters surrounding the island to obtain underwater topographic data, and then integrate the underwater topographic data with the three-dimensional spatial model of the island in S2 to generate a full-element three-dimensional dynamic map that includes the island, coastline, and underwater topography. S4: Conduct UAV aerial surveys of the island and reef areas during low tide to obtain orthophotos of the reef distribution. Extract reef boundaries and development and utilization information through image interpretation technology. Overlay the interpretation results with the full-element 3D dynamic map of S3 to generate a comprehensive distribution map of the reef area. S5: Input the full-element three-dimensional dynamic map, the comprehensive distribution map of the reef area and ecological parameters into the ecological assessment model. By integrating shoreline stability, water depth change and biodiversity data, calculate the island resource development intensity and ecological risk level, and output the island ecological assessment report. S6: Based on the island ecological assessment report, generate a 3D visualization scene, a heat map of reef development and utilization, and an island resource monitoring report.

[0021] S1 specifically includes: S11: Plan the drone aerial survey route within the target island area, set the flight altitude, flight path overlap rate and ground resolution, and use a multi-rotor drone equipped with a high-resolution RGB camera to take aerial photos along the set route to obtain high-definition image data covering the entire area of ​​the target island. S12: Perform image quality checks on the high-definition image data obtained in S11, use aerial triangulation to perform image stitching and orthorectification, and generate orthorectified image data of the target island area. S13: Acquire historical remote sensing image data and shoreline mapping data of the target island, and preprocess the remote sensing images, including radiometric correction, geometric correction and image enhancement, to ensure that the historical data matches the current orthophoto data in spatial coordinates and image quality. S14: Using a human-computer interactive interpretation method, based on the orthophoto data generated in S12, the historical remote sensing image data and shoreline mapping data processed in S13 are overlaid to extract the target island's shoreline type information, terrain feature information and development activity area information, respectively. S15: Based on the shoreline type information, terrain feature information, and development activity area information interpreted in S14, the data is integrated and classified according to geospatial location to establish a target island remote sensing image interpretation information database composed of vector data and attribute data. Through the above steps, the acquisition process and data processing methods of UAV aerial survey data are clarified, and the technical path for the fusion interpretation of historical remote sensing images and shoreline mapping data is specified. This ensures that the data content in the remote sensing image interpretation information database is rich, accurate, and spatially precise, providing a reliable foundation for data reference in subsequent steps.

[0022] S2 specifically includes: S21: Based on the shoreline distribution information in the remote sensing image interpretation database established in S1, a GNSS reference station is set up on the shoreline of the target island. The GNSS rover is used to conduct on-site reconnaissance and measurement along the shoreline location marked in the interpretation database to obtain the shoreline location information. S22: During the field measurement in S21, the GNSS measurement system was used to determine the coordinates of the inflection points at the locations of changes in the island's coastline morphology, and the coordinates of the type boundary points were measured at the locations where the coastline landform types changed. The characteristic locations of severely eroded areas were measured to obtain the coordinates and landform feature data of the eroded areas. S23: Based on the field coordinate data obtained from measurements in S21 and S22, and combined with the remote sensing image interpretation information database established in S1, the field measurement data and remote sensing image data are spatially matched using 3D geographic information system software, and a high-precision digital terrain model of the island is established through spatial interpolation. S24: Import the island digital terrain model established in S23 with the shoreline inflection points, shoreline type boundary points and erosion zone feature data obtained on site into the 3D modeling software ContextCapture. Based on the oblique photogrammetry 3D reconstruction method, perform spatial data fusion modeling to generate a target island spatial 3D model with a real spatial location. The above steps clarify the method and data processing technology for the GNSS measurement system to acquire shoreline field measurement data, realize the accurate fusion of remote sensing images and field measurement data, and ensure the reliability and data accuracy of the spatial 3D model.

[0023] S23 specifically includes: S231: Perform coordinate transformation on the GNSS field measurement coordinate data and elevation data obtained in S21 and S22, and unify them to the same geographic coordinate system as the remote sensing image interpretation information database established in S1. S232: Import the unified coordinate and elevation data from S231 into the 3D geographic information system software, use the Delaunay triangulation algorithm to generate an irregular triangular network, and establish the basic triangular surface data structure. Specifically, let each set of three points be denoted as A, B, and C, with the plane coordinates of A being X and Y, B being U and V, and C being G and H. Let the coordinates of the circumcircle's center be X0 and Y0, and the radius of the circumcircle be R. Let the denominator be D. The following formula is used to determine the triangular element that does not contain any points other than A, B, and C inside the circumcircle: D = 2 × [X×(V - H) + U×(H - Y) + G×(Y - V)]; X0 = [ (X² + Y²)×(V - H) + (U² + V²)×(H - Y) + (G² + H²)×(Y - V ) ]÷ D; Y0 = [ (X² + Y²)×(G - U) + (U² + V²)×(X - G) + (G² + H²)×(U - X ) ]÷ D; R = ((X - X0)² + (Y - Y0)² ; In the above formula, X, Y, U, V, G, and H represent the coordinates of three points A, B, and C in the plane, respectively; X0 and Y0 represent the coordinates of the center of the circumcircle of the triangle formed by A, B, and C; R represents the radius of the circumcircle; and D represents the denominator coefficient in the calculation of the circumcircle coordinates. This step ensures that each triangle satisfies the Delaunay empty circle property by checking whether the circumcircle contains any points other than A, B, and C, forming a high-fidelity irregular triangular mesh, which lays an accurate geometric foundation for subsequent interpolation processing.

[0024] S233: For the data points in the remaining uncovered areas of the irregular triangular network generated in S232, the elevation is calculated using inverse distance-weighted interpolation. The interpolation formula is: ,in, Here is the elevation value of the point to be interpolated. Let be the elevation value of the i-th known measurement point. Let p be the plane distance between the point to be interpolated and the i-th known measurement point, and let p be the exponent. During the interpolation process, an appropriate exponent is selected based on the shoreline morphology and terrain complexity to ensure that the interpolation results are accurate and reliable. S234: After interpolation is completed in S233, the interpolation result is overlaid with the orthophoto data obtained in S1 using 3D geographic information system software. The elevation and image are then fused according to geographic coordinates to generate a digital terrain model of the island. The above steps, through a combination of Delaunay triangulation and inverse distance weighted interpolation, achieve accurate data compensation for areas with large local elevation differences on the island, ensuring the elevation resolution and realism of the digital terrain model of the island, and providing higher accuracy and stability for the subsequent generation of a spatial 3D model.

[0025] S24 specifically includes: S241: Import the island digital terrain model generated in S233, the orthophoto data obtained in S1, and the reef area data obtained in S14 into the 3D modeling software ContextCapture to ensure the spatial consistency of each data within the same geographic coordinate system. S242: Oblique photogrammetry 3D reconstruction technology is used on the imported orthophoto data. Local feature matching algorithm is used to extract feature points of each image to form a set of matching points. Where x represents the horizontal coordinate of the target point in the image, y represents the vertical coordinate of the target point in the image, and z represents the elevation value corresponding to the matching point; S243: Based on the set of matching points, the external orientation elements of each image are determined using the principle of collinearity. The calculation formula is as follows: ; Where i is the horizontal coordinate of the target point in the image; p is the horizontal coordinate of the principal point of the camera image; j is the vertical coordinate of the target point in the image; q is the vertical coordinate of the principal point of the camera image; F is the camera focal length, reflecting the imaging scale of the camera optical system; O is the coordinate vector of the target point in space, denoted as (X, Y, Z); C is the coordinate vector of the camera center in space, denoted as... ; The first row vector of the rotation matrix represents the rotation component in the horizontal direction of the image; The second row vector of the rotation matrix represents the rotation component in the vertical direction of the image; The third row vector of the rotation matrix is ​​used to normalize the image coordinates; S244: After determining the external orientation elements of each image, multi-view stereo matching technology is used to reconstruct dense point clouds from the matching point set, generating 3D point cloud data of the target island. Then, a mesh construction algorithm is used to construct a triangular mesh from the 3D point cloud, and combined with texture mapping technology, orthophoto data and reef area data are superimposed on the mesh surface to complete spatial data fusion modeling and generate a 3D spatial model of the target island with a real spatial location. Through the above steps, high-precision spatial fusion and 3D reconstruction of multiple data sources are achieved, ensuring high accuracy in the real positioning and detail representation of the target island's 3D spatial model, providing solid technical support and data foundation for island resource monitoring and management.

[0026] S3 specifically includes: S31: Use a single-beam echo sounder to acquire underwater topographic data of the sea area surrounding the target island, record the coordinates of the start and end points of the survey line and the water depth value, and unify the obtained data into the same coordinate system as the three-dimensional spatial model of the island generated in S2; S32: The underwater topographic data obtained in S31 is imported into the 3D geographic information system software and overlaid with the 3D spatial model of the island generated in S2. The coordinate matching and geometric alignment of the island land topography and the sea water depth distribution are performed to ensure the seamless connection between the island land boundary and the underwater topography. S33: Use spatial interpolation methods to grid the discrete measurement points of underwater topographic data, interpolate the seabed elevation values ​​of uncovered areas, and fuse the resulting underwater digital topographic model with the island and land digital topographic model to form a unified three-dimensional dataset of island, land and underwater. S34: Import the 3D dataset obtained after fusion in step S33 into 3D modeling software, perform topology checks and surface stitching on the underwater topographic mesh and the island and land topographic mesh, and overlay the shoreline distribution information retained in S2 to generate a full-element 3D dynamic map that simultaneously includes the island and land, shoreline and underwater topography; the above steps unify the coordinates, interpolate and fuse and stitch the underwater topographic data obtained by the single-beam echo sounder with the island spatial 3D model generated in S2 to form a 3D dataset that includes the island and land, shoreline and underwater topography, providing complete and dynamic 3D visualization support for island resource monitoring and management.

[0027] S4 specifically includes: S41: During low tide, use drones to conduct aerial surveys of the target island reef area and obtain high-definition aerial images covering the reef area according to the planned flight route; S42: Import the high-definition aerial images acquired in S41 into the image processing software, perform relative and absolute orientation corrections, generate orthophoto data of the reef area using aerial triangulation, and use the same coordinate system to maintain consistency with the full-element three-dimensional dynamic map obtained in S3. S43: Apply image interpretation technology to extract features from the orthophoto data obtained in step S42, identify the boundary of the reef area based on the classification method of spectral features and texture features, and mark the development and utilization areas on the reef in combination with historical development data to obtain the boundary information and development and utilization information of the reef area. S44: Load the reef area boundary information and development and utilization information obtained in S43 into the full-element 3D dynamic map environment of S3. Use coordinate overlay and spatial matching functions to fuse the reef area data with the island, land and underwater topography to form a complete comprehensive distribution map of the reef area and realize the visualization of the reef area attribute information in the 3D scene. Through the above steps, the accurate positioning and 3D display of the reef boundary and development area are ensured, and the organic integration of the reef area image interpretation results and the full-element 3D dynamic map is realized, providing more complete and intuitive data support for island resource monitoring and subsequent management planning.

[0028] S43 specifically includes: S431: Perform spectral analysis on the orthophoto data acquired in S42, extract multispectral band data from the image, and calculate the Normalized Difference Water Index (NDWI) for the reef area to enhance the contrast between the reef and the water. The calculation formula is as follows: Wherein, NDWI is the Normalized Difference Water Index; G is the green band reflectance; NIR is the near-infrared band reflectance; when the NDWI value is greater than a set threshold... When the NDWI value is below a certain level, the area is identified as a body of water; when the NDWI value is below a certain level... and above the threshold At that time, the area was identified as a reef area; S432: Perform texture feature analysis on the image area identified as a reef area in S431, calculate the Local Binary Pattern (LBP) value to extract the surface roughness features of the reef, and the calculation formula is as follows: ,in, The local binary mode value represents the texture encoding of the center pixel; P is the number of neighborhood points of the pixel; R is the neighborhood radius. The grayscale value of the neighboring points; The grayscale value of the center pixel; For symbolic functions, the definition is as follows: The LBP value for the reef area will be calculated and compared with the threshold. Compare the values; if the LBP value is greater than... If the condition is met, the area is determined to be a rough reef area; otherwise, it is determined to be a smooth reef area. S433: Combining historical development data, acquire the developed and utilized areas in historical remote sensing images, and calculate the Development Change Index (DCI) using a time-series change detection method. The calculation formula is as follows: Among them, DCI stands for Development Change Index; This represents the average reflectance of the developed and utilized area in the current year. This represents the average reflectance of the developed and utilized area in the previous period; when the DCI exceeds the set threshold... If the area is deemed a newly developed area, it will be classified as such; otherwise, it will remain in its original development and utilization status. S434: Combining the reef area boundary information, reef surface roughness classification information, and development and utilization area information calculated from S431, S432, and S433, an interpretation layer for the reef area is constructed and geometrically vectorized. Finally, the reef area boundary information and development and utilization information are output. Through the above technical methods, the reef area boundary is accurately identified based on spectral and texture feature classification methods, and the development and utilization area on the reef is extracted by combining historical development data. This achieves high-precision interpretation of reef area information and provides complete data support for island resource monitoring.

[0029] S5 specifically includes: S51: Obtain the full-element 3D dynamic map of S3, the comprehensive distribution map of the reef area of ​​S4, and the ecological parameter data from the island's historical ecological monitoring database, and load the above data into the same ecological assessment model platform to achieve unified management of the island's overall topography, coastline, reef area, and ecological parameters. S52: In the ecological assessment model platform, the island resource development intensity is calculated based on the ratio between the developed land area and the total island-mainland area, and denoted as D. The calculation formula is as follows: Where D represents resource development intensity; This is the sum of the areas of all developed land on the island; The total land area of ​​the island; when D exceeds a predetermined threshold, it is assessed as a high-intensity development area, otherwise it is assessed as a low-intensity development area; S53: Combining the boundary information of ecologically sensitive areas extracted from the comprehensive distribution map of reef areas, and the biodiversity indicators and environmental pressure indicators from the island's historical ecological monitoring database, a comprehensive ecological risk assessment model is established to comprehensively calculate the island's ecological risk level, denoted as U. The calculation formula is as follows: Where U represents the ecological risk level; B represents the biodiversity index; and E represents the environmental pressure index. , U is a weighting coefficient, set in the model according to the characteristics of island habitats and monitoring needs; when U exceeds the set threshold, it is judged as a high ecological risk level, requiring increased ecological protection efforts; otherwise, it is judged as a low ecological risk level. S54: The calculation results of S52 and S53 are comprehensively evaluated with the results of the shoreline stability analysis to form an island ecological assessment report, which lists the island resource development intensity level, ecological risk level and shoreline stability status, and marks the geographical location and management points of high-risk areas; and proposes protection and restoration measures for high-intensity and high-risk areas in the ecological assessment report. Combining the full-element three-dimensional dynamic map and the comprehensive distribution map of reef areas, it provides differentiated resource protection and ecological restoration plans for island management departments, so as to achieve refined monitoring and management of island resources and ecological environment.

[0030] S6 specifically includes: S61: Based on a 3D geographic information system platform, the information on high-risk areas and resource development intensity levels in the island ecological assessment report is visualized and overlaid onto a full-element 3D dynamic map to generate an interactive 3D visualization scene that highlights the stability of the coastline, development intensity, and distribution of ecological risks. S63: Based on the statistical results of reef development and utilization in the assessment report, and combined with the comprehensive distribution map of the reef area, the land use of the existing, under construction and potential development areas on the reef is weighted and allocated. The spatial analysis function of the geographic information system is used to generate a heat map of reef development and utilization, which intuitively reflects the distribution and density of development hotspots. S64: Based on 3D visualization scenes and heat maps of reef development and utilization, summarize indicators of ecological risk levels, distribution of high-risk areas, and resource protection needs to compile island resource monitoring reports, including the overall resource status of the island, the current status of shoreline and reef area development and utilization, the distribution of ecologically sensitive areas, management measures, and recommendations. Through the above technical measures, the island ecological assessment report is deeply integrated with the 3D visualization scene and the heat map of reef development and utilization, which can simultaneously display the spatial distribution and risk status of the island's land area and reef area. This facilitates managers to conduct comprehensive assessments and scientific decisions on island resources and the ecological environment, improving the efficiency and accuracy of island monitoring and planning.

[0031] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for monitoring resources of uninhabited islands based on a spatial three-dimensional model, characterized in that, Includes the following steps: S1: Obtain orthophoto data of the target island through UAV aerial survey, and combine it with historical remote sensing images and coastline mapping data to establish a remote sensing image interpretation database containing information on island coastline type, terrain features and development activities; S2: Based on the remote sensing image interpretation information database, the island coastline is measured in the field using the GNSS measurement system to obtain coastline inflection points, type boundary points and erosion zone characteristic data, and a three-dimensional spatial model of the island containing the island topography and coastline distribution is generated using three-dimensional modeling software. S3: Conduct water depth measurements in the waters surrounding the island to obtain underwater topographic data, and then integrate the underwater topographic data with the three-dimensional spatial model of the island in S2 to generate a full-element three-dimensional dynamic map that includes the island, coastline, and underwater topography. S4: Conduct UAV aerial surveys of the island and reef areas during low tide to obtain orthophotos of the reef distribution. Extract reef boundaries and development and utilization information through image interpretation technology. Overlay the interpretation results with the full-element 3D dynamic map of S3 to generate a comprehensive distribution map of the reef area. S5: Input the full-element three-dimensional dynamic map, the comprehensive distribution map of the reef area and ecological parameters into the ecological assessment model. By integrating shoreline stability, water depth change and biodiversity data, calculate the island resource development intensity and ecological risk level, and output the island ecological assessment report. S6: Based on the island ecological assessment report, generate a 3D visualization scene, a heat map of reef development and utilization, and an island resource monitoring report.

2. The method for monitoring uninhabited island resources based on a spatial three-dimensional model according to claim 1, characterized in that, S1 specifically includes: S11: Plan the drone aerial survey route within the target island area, set the flight altitude, flight path overlap rate and ground resolution, and use a multi-rotor drone equipped with a high-resolution RGB camera to take aerial photos along the set route to obtain high-definition image data covering the entire area of ​​the target island. S12: Perform image quality checks on the high-definition image data obtained in S11, use aerial triangulation to perform image stitching and orthorectification, and generate orthorectified image data of the target island area. S13: Acquire historical remote sensing image data and coastline mapping data of the target island, and preprocess the remote sensing images, including radiometric correction, geometric correction and image enhancement. S14: Using a human-computer interactive interpretation method, based on the orthophoto data generated in S12, the historical remote sensing image data and shoreline mapping data processed in S13 are overlaid to extract the target island's shoreline type information, terrain feature information and development activity area information, respectively. S15: Based on the shoreline type information, terrain feature information, and development activity area information interpreted in S14, integrate and classify the data according to geospatial location, and establish a target island remote sensing image interpretation information database composed of vector data and attribute data.

3. The method for monitoring uninhabited island resources based on a spatial three-dimensional model according to claim 1, characterized in that, S2 specifically includes: S21: Based on the shoreline distribution information in the remote sensing image interpretation database established in S1, a GNSS reference station is set up on the shoreline of the target island. The GNSS rover is used to conduct on-site reconnaissance and measurement along the shoreline location marked in the interpretation database to obtain the shoreline location information. S22: During the field measurement in S21, the GNSS measurement system was used to determine the coordinates of the inflection points at the locations of changes in the island's coastline morphology, and the coordinates of the type boundary points were measured at the locations where the coastline landform types changed. The characteristic locations of severely eroded areas were measured to obtain the coordinates and landform feature data of the eroded areas. S23: Based on the field coordinate data obtained from measurements in S21 and S22, and combined with the remote sensing image interpretation information database established in S1, the field measurement data and remote sensing image data are spatially matched using 3D geographic information system software, and a high-precision digital terrain model of the island is established through spatial interpolation. S24: Import the island digital terrain model established in S23 with the shoreline inflection points, shoreline type boundary points and erosion zone feature data obtained on site into the 3D modeling software ContextCapture. Based on the oblique photogrammetry 3D reconstruction method, perform spatial data fusion modeling to generate a target island spatial 3D model with real spatial location.

4. The method for monitoring uninhabited island resources based on a spatial three-dimensional model according to claim 3, characterized in that, S23 specifically includes: S231: Perform coordinate transformation on the GNSS field measurement coordinate data and elevation data obtained in S21 and S22, and unify them to the same geographic coordinate system as the remote sensing image interpretation information database established in S1. S232: Import the unified coordinate and elevation data from S231 into the 3D geographic information system software, use the Delaunay triangulation algorithm to generate an irregular triangular network, and establish the basic triangular surface data structure. S233: For the data points in the remaining uncovered areas of the irregular triangular network generated in S232, the elevation is calculated using inverse distance-weighted interpolation. The interpolation formula is: ,in, Here is the elevation value of the point to be interpolated. Let be the elevation value of the i-th known measurement point. is the planar distance between the point to be interpolated and the i-th known measurement point, and p is the exponent; S234: After interpolation is completed in S233, the interpolation result is overlaid with the orthophoto data obtained in S1 using 3D geographic information system software. The elevation and image are then fused according to the geographic coordinates to generate a digital terrain model of the island.

5. The method for monitoring uninhabited island resources based on a spatial three-dimensional model according to claim 5, characterized in that, S24 specifically includes: S241: Import the island digital terrain model generated in S233, the orthophoto data obtained in S1, and the reef area data obtained in S14 into the 3D modeling software ContextCapture to ensure the spatial consistency of each data within the same geographic coordinate system. S242: The imported orthophoto data is reconstructed using oblique photogrammetry 3D reconstruction technology. Local feature matching algorithm is used to extract feature points of each image to form a set of matching points. S243: Based on the set of matching points, determine the external orientation elements of each image using the principle of collinearity; S244: After determining the external orientation elements of each image, multi-view stereo matching technology is used to reconstruct dense point clouds of the matching point set to generate three-dimensional point cloud data of the target island; then, a mesh construction algorithm is used to construct a triangular mesh of the three-dimensional point cloud, and combined with texture mapping technology, orthophoto data and reef area data are superimposed on the mesh surface to complete spatial data fusion modeling and generate a three-dimensional spatial model of the target island with a real spatial location.

6. The method for monitoring uninhabited island resources based on a spatial three-dimensional model according to claim 1, characterized in that, S3 specifically includes: S31: Use a single-beam echo sounder to acquire underwater topographic data of the sea area surrounding the target island, record the coordinates of the start and end points of the survey line and the water depth value, and unify the obtained data into the same coordinate system as the three-dimensional spatial model of the island generated in S2; S32: The underwater topographic data obtained in S31 is imported into the 3D geographic information system software and overlaid with the 3D spatial model of the island generated in S2. The coordinate matching and geometric alignment of the island land topography and the sea water depth distribution are performed to ensure the seamless connection between the island land boundary and the underwater topography. S33: Use spatial interpolation methods to grid the discrete measurement points of underwater topographic data, interpolate the seabed elevation values ​​of uncovered areas, and fuse the resulting underwater digital topographic model with the island and land digital topographic model to form a unified three-dimensional dataset of island, land and underwater. S34: Import the 3D dataset obtained after fusion in step S33 into 3D modeling software, perform topology checks and surface stitching on the underwater terrain mesh and the island and land terrain mesh, and overlay the shoreline distribution information retained in S2 to generate a full-element 3D dynamic map that includes islands, land, shoreline and underwater terrain.

7. The method for monitoring uninhabited island resources based on a spatial three-dimensional model according to claim 1, characterized in that, S4 specifically includes: S41: During low tide, use drones to conduct aerial surveys of the target island reef area and obtain high-definition aerial images covering the reef area according to the planned flight route; S42: Import the high-definition aerial images acquired in S41 into the image processing software, perform relative and absolute orientation corrections, generate orthophoto data of the reef area using aerial triangulation, and use the same coordinate system to maintain consistency with the full-element three-dimensional dynamic map obtained in S3. S43: Apply image interpretation technology to extract features from the orthophoto data obtained in step S42, identify the boundary of the reef area based on the classification method of spectral features and texture features, and mark the development and utilization areas on the reef in combination with historical development data to obtain the boundary information and development and utilization information of the reef area. S44: Load the reef area boundary information and development and utilization information obtained in S43 into the full-element three-dimensional dynamic map environment of S3, and use coordinate overlay and spatial matching functions to fuse the reef area data with the island, land and underwater topography to form a complete comprehensive distribution map of the reef area.

8. The method for monitoring uninhabited island resources based on a spatial three-dimensional model according to claim 7, characterized in that, Specifically, S43 includes: S431: Perform spectral analysis on the orthophoto data acquired in S42, extract multispectral band data from the image, and calculate the Normalized Difference Water Index (NDWI) for the reef area; when the NDWI value is greater than a set threshold... When the NDWI value is below a certain level, the area is identified as a body of water; when the NDWI value is below a certain level... and above the threshold At that time, the area was identified as a reef area; S432: Perform texture feature analysis on the image region identified as a reef area in S431, calculate the Local Binary Pattern (LBP) value; and compare the calculated LBP value of the reef area with a threshold. Compare the values; if the LBP value is greater than... If the condition is met, the area is determined to be a rough reef area; otherwise, it is determined to be a smooth reef area. S433: Combine historical development data to obtain developed and utilized areas in historical remote sensing images, and calculate the Development Change Index (DCI) using a time-series change detection method; when the DCI exceeds a set threshold... If the area is deemed a newly developed area, it will be classified as such; otherwise, it will remain in its original development and utilization status. S434: Combining the reef area boundary information, reef surface roughness classification information, and development and utilization area information calculated by S431, S432, and S433, construct the reef area interpretation layer, perform geometric vectorization processing, and finally output the reef area boundary information and development and utilization information.

9. The method for monitoring uninhabited island resources based on a spatial three-dimensional model according to claim 1, characterized in that, S5 specifically includes: S51: Obtain the full-element 3D dynamic map of S3, the comprehensive distribution map of the reef area of ​​S4, and the ecological parameter data from the island's historical ecological monitoring database, and load the above data into the same ecological assessment model platform to achieve unified management of the island's overall topography, coastline, reef area, and ecological parameters. S52: In the ecological assessment model platform, the island resource development intensity is calculated based on the ratio between the developed land area within the island and the total island area, and is denoted as D; when D exceeds a predetermined threshold, it is rated as a high-intensity development area, otherwise it is rated as a low-intensity development area. S53: Combining the boundary information of ecologically sensitive areas extracted from the comprehensive distribution map of reef areas, and the biodiversity indicators and environmental pressure indicators in the island's historical ecological monitoring database, establish an ecological risk comprehensive evaluation model to comprehensively calculate the island's ecological risk level and record it as U; when U exceeds the set threshold, it is judged as a high ecological risk level, otherwise it is judged as a low ecological risk level. S54: The calculation results of S52 and S53 are combined with the results of the shoreline stability analysis to form an island ecological assessment report, which lists the island resource development intensity level, ecological risk level and shoreline stability status, and marks the geographical location and management points of high-risk areas.

10. A method for monitoring uninhabited island resources based on a spatial three-dimensional model according to claim 1, characterized in that, S6 specifically includes: S61: Based on a 3D geographic information system platform, the information on high-risk areas and resource development intensity levels in the island ecological assessment report is visualized and overlaid onto a full-element 3D dynamic map to generate a 3D visualization scene with interactive functions. S63: Based on the statistical results of reef development and utilization in the assessment report, and combined with the comprehensive distribution map of the reef area, the land use of the existing, under construction and potential development areas on the reef is weighted and allocated. The spatial analysis function of the geographic information system is used to generate a heat map of reef development and utilization, which intuitively reflects the distribution and density of development hotspots. S64: Based on 3D visualization scenes and heat maps of reef development and utilization, summarize indicators of ecological risk level, distribution of high-risk areas and resource protection needs, and compile island resource monitoring reports, including the overall resource status of the island, the current status of shoreline and reef area development and utilization, distribution of ecologically sensitive areas, management measures and recommendations.

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