Island microscopic landform remote sensing classification method based on DEM and Geomorphs methods

Abstract

The invention discloses a DEM and Geomorphs method-based island microscopic landform remote sensing classification method, and relates to the technical field of island landform classification, and the method comprises the steps of island image and water depth data acquisition, island underwater DEM model construction, microscopic landform type division and classification result verification. And establishing a DEM model corresponding to the island reef, extracting each microscopic landform feature corresponding to the island reef, performing division to obtain the corresponding microscopic landform type of the island reef, verifying the correctness of division of the corresponding microscopic landform type of the island reef, and performing corresponding classification adjustment so as to realize efficient island reef microscopic landform remote sensing classification. And corresponding island development and utilization are executed, so that the precision of island landform classification is improved, the island landform classification efficiency is improved, and ecological protection and resource management are facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of island and reef landform classification, and in particular to an island and reef micro-landform remote sensing classification method based on DEM and Geomorphons method. Background Art

[0002] As one of the most basic natural elements, topography constitutes landforms of different characteristics and also affects the changes of different geographical processes. Topography classification and extraction are the basis for studying hydrological geomorphology, predicting species distribution, and describing habitat classification. Through remote sensing technology, the corresponding water depth data of each macroscopic landform type of coral islands and reefs is inverted, and the optimal high-resolution DEM data of the entire coral islands and reefs is analyzed. Based on this, the micro-landform type extraction model is constructed based on DEM and Geomorphons method technology to verify whether the micro-landform classification results of coral islands and reefs are consistent with the landform comparison of the actual water depth section, so as to accurately, quickly and efficiently grasp the topographic and geomorphic characteristics of islands and reefs, and directly serve the protection and sustainable development of island and reef areas.

[0003] Prior art, such as the invention patent application with announcement number CN118196565A, discloses an ecosystem service optimization assessment method based on mountain micro-geomorphological feature analysis, including: performing topographic and geomorphological division on the mountain area, and based on the Geomorphons method, performing micro-geomorphological type division on the mountain area to obtain mountain location information; obtaining the mountain forest type according to the mountain location information; based on the mountain forest type, obtaining the regional ratio vegetation index variation coefficient and the tree layer biomass of each mountain forest type according to multi-spectral unmanned aerial vehicle image acquisition and processing and tree layer investigation; using the regional ratio vegetation index variation coefficient and the tree layer biomass of each mountain forest type to respectively correct the I nVEST model habitat suitability parameters and carbon density values ​​to obtain the optimal I nVEST model; using the optimal I nVEST model to obtain the optimization assessment result of the ecosystem service, the present invention solves the problem of low accuracy of ecosystem service assessment in mountainous areas in the prior art.

[0004] The above invention is mainly to solve the problem of low accuracy of ecosystem service assessment in mountainous areas. It does not obtain images corresponding to islands and reefs by using remote sensing technology, and then establish a DEM model corresponding to the islands and reefs. It does not start from the perspective of extracting the micro-geomorphological characteristics corresponding to the islands and reefs. It is impossible to identify the morphological characteristics of the micro-geomorphology corresponding to the islands and reefs, and it is impossible to achieve accurate division of the micro-geomorphological types corresponding to the islands and reefs. Therefore, it is impossible to achieve accurate remote sensing classification of the micro-geomorphology of the islands and reefs, and it is impossible to accurately and efficiently know the micro-geomorphological types corresponding to the islands and reefs. It is impossible to directly serve the protection and sustainable development of the island and reef areas, reduce the utilization rate of the islands and reefs, and at the same time reduce the recognition speed of the island and reef geomorphological types, and cannot achieve the comprehensive sustainable development of the islands and reefs, and cannot achieve comprehensive utilization of island and reef resources. Summary of the invention

[0005] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a remote sensing classification method for island and reef micro-topography based on DEM and Geomorphons method.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solution: The present invention provides a remote sensing classification method of island and reef micro-geomorphology based on DEM and Geomorphons method, comprising:

[0007] Step 1: Obtain island and reef images and water depth data: Obtain the images and water depth data corresponding to the islands and reefs by using remote sensing technology, and then pre-process them to obtain the images and water depth data required for constructing the underwater digital elevation (DEM) model of the islands and reefs.

[0008] Step 2: Construction of underwater DEM model of islands and reefs: Based on the images of islands and reefs, the macro-geomorphic types are divided. Combined with the water depth data, a water depth remote sensing inversion model is established in each landform type. The water depth data of the entire island and reef is merged to construct the underwater DEM model corresponding to the island and reef.

[0009] Step 3: Classification of micro-geomorphological types: Based on the underwater DEM model of islands and reefs, the surface morphology is truly restored, and the characteristics of each micro-geomorphological type corresponding to the islands and reefs are extracted, and then the micro-geomorphological types corresponding to the islands and reefs are classified.

[0010] Step 4: Verification of classification results: Based on the classification, the micro-geomorphological types corresponding to the islands and reefs are obtained, and then the correctness of the classification of the micro-geomorphological types corresponding to the islands and reefs is verified, and the classification adjustment method of the micro-geomorphological types corresponding to the islands and reefs is analyzed.

[0011] 1. Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides a remote sensing classification method for island and reef micro-geomorphology based on DEM and Geomorphons methods. By acquiring the images and water depth data corresponding to the island and reef, a DEM model corresponding to the island and reef is established to identify the morphological features of the micro-geomorphology corresponding to the island and reef, and the corresponding micro-geomorphology type of the island and reef is divided. At the same time, the correctness of the division of the micro-geomorphology type corresponding to the island and reef is verified, and then the corresponding classification adjustment is performed, so as to achieve efficient remote sensing classification of island and reef micro-geomorphology and perform the corresponding island and reef development and utilization. By analyzing the terrain undulations, accurate extraction of micro-geomorphology features is achieved, thereby improving the accuracy of island and reef geomorphology classification, and solving the deficiencies in the current technology. At the same time, the Geomorphons technical method utilizes the geometric shape and spatial relationship characteristics of the micro-geomorphology type to achieve relatively automated classification, reduce the workload of manual processing, and improve the efficiency of island and reef geomorphology classification. The present invention provides more detailed observations, which is helpful for ecological protection and resource management, thereby realizing the comprehensive development of islands and reefs and island and reef resources, implementing comprehensive integrated landforms and landform resource utilization, providing rich and effective data support for the sustainable development of islands and reefs, and helping to formulate scientific and reasonable island and reef development and management strategies.

[0012] 2. In the acquisition of island and reef images and water depth data, the present invention pre-processes the images corresponding to the islands and reefs and divides them into macro-geomorphological types to invert high-precision water depth data of each macro-geomorphological type, and realizes an overall high-precision DEM model corresponding to the islands and reefs, thereby realizing the surface morphology analysis corresponding to the islands and reefs, accurately reflecting the current status of the three-dimensional surface morphology of the islands and reefs, thereby implementing a more vivid and intuitive micro-geomorphological remote sensing classification model.

[0013] 3. In the extraction of micro-geomorphological type features and morphological division, the present invention obtains the characteristics of each micro-geomorphological type corresponding to the islands and reefs through a three-dimensional DEM model, and identifies each micro-geomorphological type corresponding to the islands and reefs, thereby dividing the corresponding micro-geomorphological types of the islands and reefs, thereby achieving a more accurate classification of the micro-geomorphological types of islands and reefs, and thus better understanding the micro-geomorphological conditions corresponding to the current islands and reefs, and achieving efficient, rapid and accurate remote sensing classification of island and reef micro-geomorphology.

[0014] 4. In the verification of classification results, the present invention verifies the correctness of the classification of the micro-geomorphological types corresponding to the islands and reefs, and then analyzes the classification adjustment method of the micro-geomorphological types corresponding to the islands and reefs, so as to ensure the correctness of the classification of the micro-geomorphological types corresponding to the islands and reefs, and realize accurate island and reef geomorphological analysis. At the same time, it also realizes the efficient development of islands and reefs to a certain extent, increases the utilization area of ​​islands and reefs, reduces the difficulty of artificial classification of island and reef geomorphology, and improves the efficiency of classified island and reef geomorphology. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 The present invention is a schematic flow chart of the steps for implementing the method.

[0017] Figure 2 This is a schematic diagram of the design of the island and reef micro-topography remote sensing classification system constructed for the present invention.

[0018] Figure 3 It is a schematic diagram of the island and reef remote sensing micro-geomorphology classification results and water depth profile verification of the present invention. DETAILED DESCRIPTION

[0019] 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.

[0020] See also Figure 1 As shown in the figure, the remote sensing classification method of island and reef micro-topography based on DEM and Geomorphons method includes: Step 1, acquisition of island and reef image and water depth data: obtaining the image and water depth data corresponding to the island and reef by using remote sensing technology, and then pre-processing to obtain the image and water depth data required for constructing the underwater digital elevation (DEM) model of the island and reef.

[0021] It should be noted that the corresponding image and water depth data information are extracted using GIS technology or remote sensing image processing technology.

[0022] It should be noted that the analysis tools for GIS technology and remote sensing image processing technology are ArcMap10.8 and ENVI5.3 respectively.

[0023] It should be noted that the satellite data used is the Gaofen-1 medium-resolution satellite image, which is multispectral data.

[0024] It should be noted that the radar water depth data used is the ICEsat-2 satellite-borne radar water depth data, which is downloaded from the data website.

[0025] As an optional implementation method, the use of remote sensing technology to obtain images and water depth data corresponding to islands and reefs, the specific acquisition process is as follows: by using remote sensing technology to perform corresponding monitoring of islands and reefs, medium and high-resolution satellites are used to perform corresponding photography of islands and reefs, thereby obtaining images corresponding to islands and reefs, and preprocessing the satellite data of islands and reefs during the image acquisition process. Among them, satellite data includes visible light, multi-spectrum and hyperspectrum, and then the satellite image data in the acquisition process is subjected to data leak detection, radiation calibration, atmospheric correction and geometric correction, so as to obtain the preprocessed images corresponding to the islands and reefs, and extract the corresponding image information from the images corresponding to the islands and reefs, wherein the image information includes the morphological boundaries of the islands and reefs and the water depth spectrum information. At the same time, by using radar remote sensing technology and field survey technology to perform corresponding detection on the islands and reefs, the water depth data corresponding to the islands and reefs is obtained, and the water depth data in the data acquisition process is preprocessed, wherein the radar water depth data includes airborne sensor data and satellite-borne sensor data. The radar water depth data of islands and reefs are subjected to denoising, refraction correction, intra-grid data averaging and tidal correction. The water depth data from field surveys are subjected to intra-grid data averaging and tidal correction to obtain water depth values ​​corresponding to the grid spatial resolution of the island and reef satellite image data.

[0026] Step 2: Construction of underwater DEM model of islands and reefs: Based on the images of islands and reefs, the macro-geomorphic types are divided, and combined with the water depth data, a water depth remote sensing inversion model is established in each landform type, and the water depth data of the entire island and reef is merged to construct the underwater DEM model corresponding to the island and reef;

[0027] It should be noted that macro-geomorphological types include reef slopes, reef flats, shallow lagoons, deep lagoons and point reefs.

[0028] It should be noted that the interpretation marks of macro-geomorphic types include reef slope: the spectrum is relatively uniform, dark blue, the edge is connected to the open sea, and there are many corals; reef flat: the spectrum is complex, light green or dark green, connected to the reef slope; shallow lagoon: the spectrum is uniform, bright blue, and the boundary with the reef flat is obvious, and a small part of the area is dark green; deep lagoon: the spectrum is uniform, bright blue, mainly sand, adjacent to the shallow lagoon, generally located in the center of the island reef; point reef: the spectrum is relatively complex, blue or green, typical patchy and dotted, densely distributed in the lagoon, divided into peak type and reef flat type. As an optional implementation method, the macro-geomorphic type of the island reef is identified, and the specific establishment process is as follows: based on the satellite remote sensing images corresponding to the island reef, the corresponding amplification, contrast enhancement, color adjustment and supervised classification operations are performed to establish the interpretation marks of each macro-geomorphic type, and then the macro-geomorphic type corresponding to the island reef is preliminarily identified. The identified macro-geomorphic types of islands and reefs are compared with the interpretation marks of various geomorphic types. If the characteristics of an identified macro-geomorphic type are the same as those of a reference geomorphic type, then the macro-geomorphic type is determined to be identified, thereby identifying all the macro-geomorphic types corresponding to the islands and reefs.

[0029] As an optional implementation method, the DEM model corresponding to the islands and reefs is established, and the specific establishment process is as follows: based on the satellite remote sensing images of the islands and reefs and the corresponding pre-processed water depth data, combined with the five macro-geomorphological units of reef slope, reef flat, shallow lagoon, deep lagoon and point reef drawn by remote sensing images, the band ratio binomial regression model is used to establish the water depth inversion model in the reef slope and deep lagoon landforms, and the multi-band ratio regression model is used to establish the water depth inversion model in the reef flat, shallow lagoon and point reef landforms. The water depth data of each landform is inverted by empirical methods. The water depth data obtained by inverting each landform is merged and the data is exported to obtain high-precision water depth data of different islands and reefs as a whole. The range vector of each island and reef is used as a mask, and the water depth inversion data of each island and reef is extracted according to the mask clipping, and the DEM model corresponding to the island and reef is constructed based on the obtained water depth data.

[0030] In the acquisition of island and reef images and water depth data, the present invention conducts in-depth analysis and modeling of the images and water depth data corresponding to the islands and reefs, and at the same time establishes a DEM model corresponding to the islands and reefs, thereby realizing the surface morphology monitoring and analysis corresponding to the islands and reefs, accurately reflecting the current status information of the three-dimensional surface morphology corresponding to the islands and reefs, thereby implementing a more vivid and intuitive island and reef micro-topography remote sensing classification model.

[0031] Step 3: Classification of micro-geomorphological types: Based on the underwater DEM model of islands and reefs, the surface morphology is truly restored, the characteristics of each micro-geomorphological type corresponding to the islands and reefs are extracted, and then the corresponding micro-geomorphological types of the islands and reefs are classified;

[0032] It should be noted that terrain analysis tools include SAGA7.9 and MATLABR2022b.

[0033] It should be noted that the values ​​on the X-axis and Y-axis are the number of columns and rows of the grid data, and the Z value is the water depth value.

[0034] As an optional implementation, the extraction obtains the characteristics of each micro-geomorphological type corresponding to the islands and reefs. The specific extraction process is as follows: first, the DEM raster data of the islands and reefs is loaded and read through the imread function in MATLAB, and then assigned to the image variable; secondly, the meshgrid function is used to generate the grid data point (x, y), and the function call format is [X, Y] = meshgrid (x, y), where x and y Represents the values ​​on the X-axis and Y-axis respectively; at the same time, after using the fliplr function to read the Z value of the raster data DEM, use the surf function to read the X , Y and ZDraw it as a three-dimensional surface; then use the colormap function to select the corresponding color mapping for drawing the three-dimensional surface, use the light function to increase the light intensity, contrast, and brightness, and use materialshiny to add shiny materials to the three-dimensional surface to truly restore the surface morphology, so as to extract the characteristics of each micro-landform type corresponding to the islands and reefs.

[0035] It should be noted that the micro-topography types include flat terrain, reef hills, reef ridges, slope shoulders, convex back slopes, straight back slopes, concave back slopes, slope feet, reef gullies or depressions, a total of 10 categories.

[0036] It should be noted that flat terrain: relatively flat surface terrain, lacking significant ups and downs, continuous large areas of flat land are common in shallow lagoons and reef flats, providing a stable ecological habitat; reef hills: raised areas formed by the growth of corals, which can be isolated or connected to form reef belts. Their three-dimensional structure can increase the complexity and biodiversity of coral reef terrain; reef ridges: a linear protrusion, usually similar to reef hills, but more slender, which has the effect of slowing down water flow. Reef ridges close to the open sea with strong hydrodynamics are often covered with seaweed and have less coral growth; slope shoulder: a gentle slope connecting part of the flat side, which is a common transition area between the reef slope and reef flat landforms, and the reef flat and shallow lagoon landforms; convex back slope: a slope protruding outward, which is a common part of the reef slope landform, providing a growth slope for corals and other organisms to attach; straight back Slope: A slope that is opposite to the convex back slope and concave back slope, which is straight and inclined downward or upward. It has a steep structure and is a typical feature of reef slope landforms. This type of micro-landform also exists in areas with large terrain changes in other geomorphic units; Concave back slope: A slope that is concave inward, which is opposite to the convex back slope. The steep structure is common in reef slope landforms and is easy to accumulate sediments and coral fragments. At the same time, the hydrodynamics here are weak, and branching corals often grow; Slope foot: The transition area where the slope surface intersects the bottom plain or deep water, which may be greatly affected by waves and tides, and is usually developed at the boundary between reef hills and deep lagoon landforms; Reef gully: A deep gully formed between reef hills or reef ridges, which is in the shape of a slender line and is mostly developed in the fore-reef slope ridge trough landform and deep lagoon landform; Depression: A low-lying area on the surface of the reef body, which is relatively flat compared to the surrounding terrain and is prone to forming shallow bays or sedimentary areas.

[0037] It should be noted that the geomorphic analysis tool is Geomorphon, the tuple {+,-,-,-,0,+,+,+} is {higher, lower, lower, lower, equal, higher, higher, higher}, the various local geometric morphological patterns are 38=6561 local geometric morphological patterns, each pattern is a unique ground monomer pattern, and there are 498 patterns that are unique ground monomer patterns.

[0038] It should be noted that the surrounding pixels are not necessarily directly adjacent pixels to the focus pixel, but are pixels determined along eight main directions according to the line of sight principle.

[0039] As an optional implementation, the division obtains the corresponding micro-geomorphological type of the islands and reefs. The specific division process is as follows: by using the geomorphological analysis tool to extract the focal pixel position corresponding to the islands and reefs, and comparing the focal pixel position with the eight adjacent pixels around it, starting from the pixel located on the east side, the counterclockwise direction is compared to generate a ternary operator, including the tuple {+, -, -, -, 0, +, +, +}, and so on, and then various local geometric morphological patterns are combined. Secondly, after eliminating all the same patterns formed by the rotation or reflection of other shapes, the remaining patterns are unique ground monomer patterns, and are classified into 10 common micro-geomorphological types. For example, when the output ground monomer grid value is 1-5, the pixels corresponding to the islands and reefs are classified as flat terrain, reef hills, reef ridges, slope shoulders, and convex back slopes in turn; when the output ground monomer grid value is 6-10, the pixels corresponding to the islands and reefs are classified as straight back slopes, concave back slopes, slope feet, reef trenches, and depressions in turn, thereby dividing the corresponding micro-geomorphological types of the islands and reefs.

[0040] The present invention obtains the micro-geomorphological features corresponding to the islands and reefs by extracting them during the extraction of micro-geomorphological features and morphological division, and identifies the micro-geomorphological morphological types corresponding to the islands and reefs, thereby dividing the micro-geomorphological types corresponding to the islands and reefs, thereby achieving a more accurate classification of the micro-geomorphological types of the islands and reefs, thereby better understanding the geomorphological conditions corresponding to the current islands and reefs, and achieving efficient, rapid, and accurate remote sensing classification of the micro-geomorphology of the islands and reefs.

[0041] Step 4: Verification of classification results: Based on the classification, the micro-geomorphological types corresponding to the islands and reefs are obtained, and then the correctness of the classification of the micro-geomorphological types corresponding to the islands and reefs is verified, and the classification adjustment method of the micro-geomorphological types corresponding to the islands and reefs is analyzed.

[0042] It should be noted that the following verification methods are also included: import the field survey water depth points in ArcMap10.8 software, display the XY data in the WGS84 coordinate system, export it into vector point data, define the projection as WGS_1984_UTM_Zone_49N, and use the "Multi-value Extraction to Point" tool to extract the values ​​of the Huaguang Reef Geomorphons classification result raster data and the Huaguang Reef water depth inversion DEM raster data generated by SAGA to the field survey water depth points, select a point close to the outer periphery of the reef slope from the field water depth points converted into vector points, export the data as the starting point, and select " The "Point Distance" tool is used to set the first point located on the reef slope as the starting point, and the other points as adjacent points. The actual distance values ​​from all adjacent points to the starting point are calculated to generate a distance table. Finally, the "Attribute Link" tool is used to link the distance table with the attribute table of the field survey water depth points after extracting multiple values. The linked attribute table is copied to the Excel table to generate a water depth profile. The landforms are divided according to the distance of the points located at the boundaries of different geomorphic areas. Secondly, the terrain conditions of different distance sections are indicated according to the micro-geomorphic values ​​represented by the points, so as to verify the correctness of the classification of the micro-geomorphic types corresponding to the islands and reefs.

[0043] As an optional implementation method, the verification of the correctness of the classification of the micro-geomorphic types to which the islands and reefs belong is specifically verified as follows: according to the classification of the micro-geomorphic types to which the islands and reefs belong, a comparison image of the micro-geomorphic types to which the islands and reefs belong is obtained, and then the comparison information of the micro-geomorphic types to which the islands and reefs belong is obtained according to the comparison image, wherein the comparison information includes similarity and precision; then the corresponding machine learning model is selected, and the comparison information of the micro-geomorphic types to which the islands and reefs belong is input into the machine learning model, and the judgment evaluation coefficient of the micro-geomorphic types to which the islands and reefs belong is obtained by analysis. When the judgment monitoring result of the classification of the micro-geomorphic types to which the islands and reefs belong is 0, it is determined that the classification of the micro-geomorphic types to which the islands and reefs belong is incorrect, and the classification method of the micro-geomorphic types to which the islands and reefs belong is adjusted; when the judgment monitoring result of the classification of the micro-geomorphic types to which the islands and reefs belong is 1, it is determined that the classification of the micro-geomorphic types to which the islands and reefs belong is correct, thereby verifying the correctness of the classification of the micro-geomorphic types to which the islands and reefs belong.

[0044] As an optional implementation method, the analysis obtains the evaluation coefficient of the micro-geomorphological type classification corresponding to the island and reef. The specific analysis process is as follows: through the calculation formula: The analysis results show that the evaluation coefficient δ of the classification of the micro-geomorphological types of islands and reefs is obtained, η is the similarity of the classification of the micro-geomorphological types of islands and reefs, μ is the accuracy of the classification of the micro-geomorphological types of islands and reefs, and z 1 、z 2are the weight factors of similarity and accuracy respectively, θ is the preset reference judgment coefficient, 0<z 1 <1,0<z 2 <1. It should be noted that the historical similarities of the micro-geomorphological types of islands and reefs are obtained from the database, and then the average similarity of the micro-geomorphological types of islands and reefs is obtained through the average value formula method, and the average similarity is used as the set reference similarity. The historical accuracy of the micro-geomorphological types of islands and reefs is obtained from the database, and then the average accuracy of the micro-geomorphological types of islands and reefs is obtained through the average value formula method, and the average accuracy is used as the set reference accuracy.

[0045] It should also be noted that the weight factors of similarity and precision are obtained through principal component analysis. The corresponding information of similarity and precision is first condensed, and then the corresponding variance explanation rate is obtained, and then divided by the variance explanation rate to obtain the corresponding weight.

[0046] It is important to note again that information condensation refers to condensing multiple analysis items into several key summary indicators, and the variance explanation rate refers to the contribution of each principal component or factor to the overall variance, usually expressed as a percentage, indicating how much information the factor contains about the original data.

[0047] As an optional implementation method, the analysis obtains the classification adjustment method of the micro-geomorphological type classification corresponding to the island and reef. The specific analysis process is as follows: the judgment and evaluation coefficient of the micro-geomorphological type classification corresponding to the island and reef is compared with the historical judgment and evaluation coefficient thresholds corresponding to the classification adjustment method stored in the database. If the judgment and evaluation coefficient of the micro-geomorphological type classification corresponding to the island and reef is the same as a historical judgment and evaluation coefficient threshold corresponding to the classification adjustment method stored in the database, then the classification adjustment method corresponding to the historical judgment and evaluation coefficient threshold is used as the classification adjustment method of the micro-geomorphological type classification corresponding to the island and reef, and the classification adjustment method of the micro-geomorphological type classification corresponding to the island and reef is obtained by analysis.

[0048] The embodiment of the present invention obtains the image and water depth data corresponding to the islands and reefs, and then establishes the DEM model corresponding to the islands and reefs, and extracts the micro-geomorphological features corresponding to the islands and reefs, thereby identifying the micro-geomorphological morphological units corresponding to the islands and reefs, dividing the corresponding micro-geomorphological types of the islands and reefs, and verifying the correctness of the classification of the micro-geomorphological types corresponding to the islands and reefs, and then performing the corresponding classification adjustment, so as to achieve efficient remote sensing classification of micro-geomorphology of islands and reefs, and perform the corresponding development and utilization of islands and reefs. By analyzing the terrain undulation, the micro-geomorphological features can be accurately extracted, thereby improving the accuracy of the classification of micro-geomorphology of islands and reefs, and solving the shortcomings in the current technology. At the same time, the Geomorphons technical method uses the geometric shape and spatial relationship characteristics of the micro-geomorphology to achieve relatively automatic classification, reduce the workload of manual processing, and improve the efficiency of island and reef geomorphological classification. The present invention provides more detailed observation, which is helpful for ecological protection and resource management, and then realizes the comprehensive development of islands and reefs and island and reef resources, implements comprehensive comprehensive geomorphology and geomorphological resource utilization, provides rich and effective data support for the sustainable development of islands and reefs, and helps to formulate scientific and reasonable island and reef development and management strategies.

[0049] The above contents are merely examples and explanations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined in this specification, they shall all fall within the protection scope of the present invention.

Claims

1. A remote sensing classification method for island and reef micro-geomorphology based on DEM and Geomorphons, characterized in that: include: Step 1: Obtain island and reef images and water depth data: Obtain the images and water depth data corresponding to the islands and reefs by using remote sensing technology, and then pre-process them to obtain the images and water depth data required for constructing the underwater digital elevation (DEM) model of the islands and reefs; Step 2: Construction of underwater DEM model of islands and reefs: Based on the images of islands and reefs, the macro-geomorphic types are divided, and combined with the water depth data, a water depth remote sensing inversion model is established in each macro-geomorphic type, and the water depth data of the islands and reefs as a whole is merged to construct the underwater DEM model corresponding to the islands and reefs; Step 3: Classification of micro-geomorphological types: Based on the underwater DEM model of islands and reefs, the surface morphology is truly restored, the characteristics of each micro-geomorphological type corresponding to the islands and reefs are extracted, and then the corresponding micro-geomorphological types of the islands and reefs are classified; Step 4: Verification of classification results: Based on the classification, the micro-geomorphological types corresponding to the islands and reefs are obtained, and then the correctness of the classification of the micro-geomorphological types corresponding to the islands and reefs is verified, and the classification adjustment method of the micro-geomorphological types corresponding to the islands and reefs is analyzed.

2. The island and reef micro-geomorphology remote sensing classification method based on DEM and Geomorphons method as claimed in claim 1, characterized in that: The specific acquisition process of using remote sensing technology to obtain images and water depth data corresponding to islands and reefs is as follows: By using remote sensing technology to carry out corresponding monitoring of islands and reefs, medium and high-resolution satellites are used to carry out corresponding photography of islands and reefs, thus obtaining corresponding images of the islands and reefs, and pre-processing the satellite data of the islands and reefs during the image acquisition process. Among them, satellite data includes visible light, multi-spectrum and hyperspectrum, and then the satellite image data in the collection process are checked for data leaks, radiation calibration, atmospheric correction and geometric correction, so as to obtain the pre-processed images corresponding to the islands and reefs, and extract the corresponding image information from the images corresponding to the islands and reefs, where the image information includes the morphological boundaries of the islands and reefs and the water depth spectrum information; at the same time, the corresponding detection of the islands and reefs is carried out by using radar remote sensing technology and field investigation technology to obtain the corresponding water depth data of the islands and reefs, and the water depth data in the data collection process are preprocessed, where the radar water depth data includes airborne sensor data and satellite-borne sensor data; the island and reef radar water depth data are denoised, refraction corrected, grid-averaged and tidal corrected, and the field survey water depth data are grid-averaged and tidal corrected to obtain the water depth value corresponding to the grid spatial resolution of the island and reef satellite image data.

3. The island and reef micro-geomorphology remote sensing classification method based on DEM and Geomorphons method as claimed in claim 1, characterized in that: The specific identification process of the macroscopic landform types of islands and reefs is as follows: Based on the satellite remote sensing images corresponding to the islands and reefs, the corresponding magnification, contrast enhancement, color adjustment and supervised classification operations are performed to establish the interpretation marks of each macro-geomorphic type, and then the macro-geomorphic types corresponding to the islands and reefs are preliminarily identified. The identified macro-geomorphic types of islands and reefs are compared with the interpretation marks of various landform types. If the characteristics of a certain identified macro-geomorphic type are the same as those of a reference landform type, the macro-geomorphic type is determined to be identified, thereby identifying all the macro-geomorphic types corresponding to the islands and reefs.

4. The island and reef micro-geomorphology remote sensing classification method based on DEM and Geomorphons method as claimed in claim 1, characterized in that: The DEM model corresponding to the islands and reefs is established, and the specific establishment process is as follows: Based on the satellite remote sensing images of islands and reefs and the corresponding pre-processed water depth data, combined with the five macro-geomorphological units of reef slope, reef flat, shallow lagoon, deep lagoon and point reef drawn by remote sensing images, the band ratio binomial regression model is used to establish the water depth inversion model in the reef slope and deep lagoon landforms, and the multi-band ratio regression model is used to establish the water depth inversion model in the reef flat, shallow lagoon and point reef landforms. The water depth data of each landform inverted by the empirical method is obtained. The water depth data obtained by inverting each landform are merged and exported to obtain high-precision water depth data of different islands and reefs as a whole. The range vector of each island and reef is used as a mask, and the water depth inversion data of each island and reef is extracted according to the mask clipping, and the DEM model corresponding to the island and reef is constructed based on the obtained water depth data.

5. The island and reef micro-geomorphology remote sensing classification method based on DEM and Geomorphons method as claimed in claim 1, characterized in that: The extraction obtains the microscopic geomorphic features corresponding to the islands and reefs, and the specific extraction process is as follows: First, the DEM raster data of the islands and reefs is loaded and read through the imread function in MATLAB, and then assigned to the image variable; secondly, the meshgrid function is used to generate grid data points (x, y), and the function call format is [X, Y] = meshgrid (x, y), where x and y represent the values ​​on the X-axis and Y-axis respectively; at the same time, the fliplr function is used to read the Z value of the raster data DEM, and the surf function is used to draw the read X, Y and Z as a three-dimensional surface; then the colormap function is used to select the corresponding color mapping for drawing the three-dimensional surface, the light function is used to increase the light source intensity, contrast, and brightness, and the materialshiny is used to add shiny materials to the three-dimensional surface to truly restore the surface morphology, so as to extract the characteristics of each micro-geomorphological type corresponding to the islands and reefs.

6. The island and reef micro-geomorphology remote sensing classification method based on DEM and Geomorphons method as claimed in claim 1, characterized in that: The above division results in the micro-geomorphological type corresponding to the islands and reefs. The specific division process is as follows: By using the geomorphic analysis tool to extract the focal pixel position corresponding to the islands and reefs, and compare the focal pixel position with the eight adjacent pixels around it, starting from the pixel located in the east, the counterclockwise direction is compared to generate a ternary operator, including the tuple {+,-,-,-,0,+,+,+}, and so on, various local geometric morphological patterns are combined. Secondly, after eliminating all the same patterns formed by the rotation or reflection of other shapes, the remaining patterns are unique ground monomer patterns, and are classified into various micro-geomorphic types in turn. For example, when the output ground monomer grid value is 1-5, the pixels corresponding to the islands and reefs are classified as flat terrain, reef hills, reef ridges, slope shoulders, and convex back slopes in turn; when the output ground monomer grid value is 6-10, the pixels corresponding to the islands and reefs are classified as straight back slopes, concave back slopes, slope feet, reef trenches, and depressions in turn, thereby dividing the corresponding micro-geomorphic types of the islands and reefs.

7. The island and reef micro-geomorphology remote sensing classification method based on DEM and Geomorphons method as claimed in claim 1, characterized in that: The verification of the correctness of the classification of the micro-geomorphological types to which the islands and reefs belong: According to the classification of the micro-geomorphic types corresponding to the islands and reefs, the comparison images of the micro-geomorphic types corresponding to the islands and reefs are obtained, and then the comparison information of the micro-geomorphic types corresponding to the islands and reefs is obtained according to the comparison images, wherein the comparison information includes similarity and precision; then the corresponding machine learning model is selected, and the comparison information of the micro-geomorphic types corresponding to the islands and reefs is input into the machine learning model, and the judgment evaluation coefficient of the micro-geomorphic types corresponding to the islands and reefs is obtained by analysis. When the judgment monitoring result of the micro-geomorphic types corresponding to the islands and reefs is 0, it is determined that the micro-geomorphic types corresponding to the islands and reefs are incorrect, and the classification method of the micro-geomorphic types corresponding to the islands and reefs is adjusted; when the judgment monitoring result of the micro-geomorphic types corresponding to the islands and reefs is 1, it is determined that the micro-geomorphic types corresponding to the islands and reefs are correctly divided, so as to verify the correctness of the micro-geomorphic types corresponding to the islands and reefs.

8. The island and reef micro-geomorphology remote sensing classification method based on DEM and Geomorphons method as claimed in claim 7, characterized in that: The above analysis obtains the evaluation coefficient of the micro-geomorphological type classification of the islands and reefs. The specific analysis process is as follows: By calculation formula: The analysis results show that the evaluation coefficient δ of the micro-geomorphological type classification of the islands and reefs is obtained, η is the similarity of the micro-geomorphological type classification of the islands and reefs, μ is the accuracy of the micro-geomorphological type classification of the islands and reefs, z1 and z2 are the weight factors of the set similarity and accuracy respectively, θ is the preset reference evaluation coefficient, 0<z1<1, 0<z2<1.

9. The island and reef micro-geomorphology remote sensing classification method based on DEM and Geomorphons method as claimed in claim 1, characterized in that: The above analysis results in the classification and adjustment of the micro-geomorphological types of islands and reefs. The specific analysis process is as follows: The judgment and evaluation coefficient of the micro-geomorphological type classification corresponding to the island and reef is compared with the historical judgment and evaluation coefficient thresholds corresponding to the classification adjustment methods stored in the database. If the judgment and evaluation coefficient of the micro-geomorphological type classification corresponding to the island and reef is the same as a historical judgment and evaluation coefficient threshold corresponding to the classification adjustment method stored in the database, the classification adjustment method corresponding to the historical judgment and evaluation coefficient threshold is used as the classification adjustment method of the micro-geomorphological type classification corresponding to the island and reef. The classification adjustment method of the micro-geomorphological type classification corresponding to the island and reef is obtained by analysis.

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