River ecological environment quality assessment method based on remote sensing image

Abstract

The invention discloses a river ecological environment quality evaluation method based on a remote sensing image, and relates to the technical field of habitat evaluation, and the method specifically comprises the following steps: obtaining multi-source remote sensing image data of a target river region, calculating each index for evaluating the river ecological environment quality according to the extracted feature parameters, and calculating the multi-source remote sensing image data of the target river region; a comprehensive evaluation index system including river ecological integrity, water quality and riparian zone stability is constructed by extracting multi-dimensional characteristic parameters such as river width, length, water area and water turbidity, key elements of a river ecological environment are comprehensively covered, and on an evaluation model, a mode of combining an analytic hierarchy process and a fuzzy comprehensive evaluation method is adopted to evaluate the river ecological environment. The weight of each index is scientifically determined through the analytic hierarchy process, and the uncertainty in the evaluation process is processed by using the fuzzy comprehensive evaluation method, so that the evaluation result better fits the actual ecological condition, and the one-sidedness caused by a single index or subjective judgment is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of habitat assessment, in particular to a river ecological environment quality assessment method based on remote sensing images. BACKGROUND

[0002] The river ecological environment is an important part of the earth's ecological system, and its quality directly affects the regional water resources security, biodiversity protection and human production and life. With the acceleration of industrialization and urbanization, rivers are facing a series of problems such as water pollution, ecological degradation, and river bank destruction. Accurate and efficient assessment of river ecological environment quality has become a key prerequisite for ecological protection and management.

[0003] Traditional river ecological environment quality assessment methods rely mainly on field sampling monitoring, which requires a large amount of manpower, material resources and time, not only high cost, but also limited by the distribution of sampling points, it is difficult to achieve large-scale, full-coverage assessment, especially for river regions with wide basins and complex terrain, the spatial representativeness is insufficient, which may lead to one-sidedness of the assessment results. At the same time, the application of a single data source is common in traditional assessment, such as relying only on water quality monitoring data or local habitat survey results, ignoring the synergistic effect of multiple factors such as hydrological morphology, vegetation coverage, and river bank stability in the river ecological system, which makes it difficult to fully reflect the overall situation of the river ecological environment. Therefore, the present application provides a river ecological environment quality assessment method based on remote sensing images. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a river ecological environment quality assessment method based on remote sensing images, which solves the problem of difficulty in achieving large-scale, full-coverage assessment, especially for river regions with wide basins and complex terrain, the spatial representativeness is insufficient, which may lead to one-sidedness of the assessment results. At the same time, the application of a single data source is common in traditional assessment, such as relying only on water quality monitoring data or local habitat survey results, ignoring the synergistic effect of multiple factors such as hydrological morphology, vegetation coverage, and river bank stability in the river ecological system, which makes it difficult to fully reflect the overall situation of the river ecological environment.

[0005] To achieve the above purpose, the present application is realized by the following technical scheme: a river ecological environment quality assessment method based on remote sensing images, characterized in that it specifically comprises the following steps: A1, obtaining multi-source remote sensing image data of the target river region, the multi-source remote sensing image data at least including optical remote sensing image data and radar remote sensing image data; A2, pre-processing the obtained multi-source remote sensing image data, the pre-processing including radiation correction, geometric correction and atmospheric correction, to obtain corrected image data for analysis; A3, extracting feature parameters related to the river ecological environment from the corrected image data, the feature parameters including but not limited to river width, river length, water area, water turbidity, vegetation coverage and land use type; A4, calculating various indexes for evaluating the river ecological environment quality according to the extracted feature parameters, the indexes including river ecological integrity index, water quality index and riparian zone stability index; A5, using a pre-constructed evaluation model to evaluate the ecological environment quality of the target river region in combination with the calculated indexes, and outputting the evaluation result.

[0006] Preferably, the remote sensing image data includes green band, red band, near-infrared band and short-wave infrared band.

[0007] Preferably, in the step of acquiring multi-source remote sensing image data of the target river region, the spatial resolution of the optical remote sensing image data is not less than 10 meters, and the temporal resolution is not less than 15 days; the spatial resolution of the radar remote sensing image data is not less than 30 meters, and the temporal resolution is not less than 30 days.

[0008] Preferably, in the process of performing radiation correction on the acquired multi-source remote sensing image data, for the optical remote sensing image data, the radiation transfer equation method is used for correction; for the radar remote sensing image data, the absolute calibration method is used for correction.

[0009] Preferably, the method for extracting the river width from the corrected image data is: B1, using an edge detection algorithm to identify the river boundary, and obtaining the river width by calculating the vertical distance between the river boundaries; B2, the method for extracting the river length is: using a center line extraction algorithm to extract the center line of the identified river region, and obtaining the river length by calculating the length of the center line.

[0010] Preferably, when calculating the water quality index, a water quality inversion model is constructed using the reflectivity characteristics of the water body in different bands, water quality parameters such as chemical oxygen demand and ammonia nitrogen content are obtained by inversion, and the inversion results are classified according to the water quality standard to obtain the water quality index evaluation result.

[0011] Preferably, the constructed evaluation model is a model combining the analytic hierarchy process and the fuzzy comprehensive evaluation method, wherein the analytic hierarchy process is used to determine the weight of each evaluation index, and the fuzzy comprehensive evaluation method is used to obtain the final river ecological environment quality evaluation result according to the index weight and the index evaluation result.

[0012] Preferably, the step of verifying the evaluation result is specifically: The field monitoring data of the target river area is collected, the field monitoring data is compared and analyzed with the evaluation result, and the accuracy and reliability of the evaluation method are verified, and after the output evaluation result, the evaluation method further includes the step of generating a river ecological environment quality evaluation report according to the evaluation result, and the evaluation report includes a description of the current situation of the river ecological environment, an analysis of the existing problems and targeted protection and improvement suggestions.

[0013] Advantages

[0014] The application provides a river ecological environment quality evaluation method based on remote sensing images. Firstly, the application obtains multi-source remote sensing image data, and performs preprocessing such as radiation correction, geometric correction and atmospheric correction on the multi-source remote sensing image data, thereby effectively eliminating errors and interference in the image data, and at the same time, the optical remote sensing image has a spatial resolution of not less than 10 meters and a time resolution of not less than 15 days, and the radar remote sensing image has a spatial resolution of not less than 30 meters and a time resolution of not less than 30 days, thereby ensuring the coverage quality of the data in the spatial and time dimensions, and the combination of multi-source data fusion and strict preprocessing provides high-precision and all-around basic data for subsequent feature parameter extraction and index calculation, thereby avoiding the limitation of a single data source.

[0015] Firstly, the application extracts multi-dimensional feature parameters such as river width, length, water area and water turbidity, and constructs a comprehensive evaluation index system including river ecological integrity, water quality and river bank stability, thereby comprehensively covering the key elements of the river ecological environment, and on the evaluation model, the combination of the analytic hierarchy process and the fuzzy comprehensive evaluation method is adopted, thereby scientifically determining the weight of each index by the analytic hierarchy process, and processing the uncertainty in the evaluation process by the fuzzy comprehensive evaluation method, so that the evaluation result is more in line with the actual ecological condition, and the one-sidedness caused by a single index or subjective judgment is avoided.

[0016] Firstly, the application is verified by the field monitoring data, thereby ensuring the accuracy and reliability, and an evaluation report including ecological status description, problem analysis and protection suggestions can be generated, and through the closed-loop process of “evaluation-verification-report”, specific and operable guidance basis for river ecological environment protection and management is provided, and at the same time, based on the non-contact monitoring characteristics of the remote sensing technology, the method is suitable for large-scale and long-term river ecological evaluation, thereby overcoming the defects of high cost and limited coverage of traditional field monitoring, and facilitating dynamic tracking of the change trend of the river ecological environment. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The flowchart of the evaluation method of the application. DETAILED DESCRIPTION

[0018] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0019] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application. Figure 1 The present application provides a technical solution: Embodiment one, a river ecological environment quality evaluation method based on remote sensing image, characterized by: specifically comprising the following steps: A1, obtaining multi-source remote sensing image data of the target river area, the multi-source remote sensing image data at least including optical remote sensing image data and radar remote sensing image data; A2, preprocessing the obtained multi-source remote sensing image data, the preprocessing including radiation correction, geometric correction and atmospheric correction, to obtain corrected image data available for analysis; A3, extracting feature parameters related to river ecological environment from the corrected image data, the feature parameters including but not limited to river width, river length, water area, water turbidity, vegetation coverage and land use type; A4, calculating various indexes for evaluating river ecological environment quality according to the extracted feature parameters, the indexes including river ecological integrity index, water quality index and riparian zone stability index; A5, using the pre-constructed evaluation model, combining the calculated various indexes, evaluating the ecological environment quality of the target river area, and outputting the evaluation result.

[0020] Among them, the above complete river ecological environment quality evaluation process from data acquisition, processing, feature extraction, index calculation to evaluation result output. This process uses multi-source remote sensing image data, combines preprocessing, feature parameter extraction, index calculation and evaluation model, etc. to realize the systematic and comprehensive evaluation of the ecological environment quality of the target river area, overcoming the defects of traditional evaluation methods such as dependence on field sampling, high cost, limited coverage and difficulty in fully reflecting the overall situation of river ecological environment.

[0021] In the embodiments of the present application, the remote sensing image data contains green band, red band, near-infrared band and short-wave infrared band. The green band has strong water penetration ability and can be used to monitor water depth and suspended solids in water. The red band and near-infrared band have significant effect in vegetation monitoring and can reflect vegetation coverage and growth conditions. The short-wave infrared band helps to identify different land use types and rock types, etc., providing a more comprehensive data source for subsequent extraction of feature parameters related to river ecological environment.

[0022] In the embodiment of the present application, in the step of acquiring multi-source remote sensing image data of the target river area, the spatial resolution of the optical remote sensing image data is not less than 10 meters, and the time resolution is not less than 15 days; the spatial resolution of the radar remote sensing image data is not less than 30 meters, and the time resolution is not less than 30 days, which ensures that the data can clearly reflect the detailed features of the river in space, such as river width and river bank condition, and can capture the dynamic changes of the river ecological environment in time, meeting the needs of large-scale, regular monitoring and evaluation of river ecological environment quality, and ensuring the accuracy and timeliness of the evaluation results.

[0023] In the embodiment of the present application, in the process of radiometric correction of the acquired multi-source remote sensing image data, the optical remote sensing image data is corrected by using the radiative transfer equation method; the radiative transfer equation method can better eliminate the influence of atmospheric scattering, absorption and other factors on the radiance of optical remote sensing image, so that the image data more truly reflects the reflection characteristics of the ground object; the absolute calibration method can convert the gray value of the radar remote sensing image into the backscattering coefficient with physical meaning, improving the quantitative analysis accuracy of the radar image data and ensuring the reliability of the corrected image data, laying a good data foundation for subsequent feature extraction and index calculation.

[0024] In the embodiment of the present application, the method for extracting the river width from the corrected image data is: B1, using an edge detection algorithm to identify the river boundary, and obtaining the river width by calculating the vertical distance between the river boundaries, which can quickly and accurately determine the boundary range of the river, and then accurately calculate the river width, providing key data for analyzing the hydrological morphological characteristics of the river; B2, the method for extracting the river length is: using a center line extraction algorithm to extract the center line of the identified river area, and obtaining the river length by calculating the length of the center line, which can effectively extract the main trend of the river, accurately calculate the river length, and help to understand the extension range and basin scale of the river, providing an important basis for evaluating the river ecological integrity and other indexes.

[0025] In the embodiment of the present application, when calculating the water quality index, the reflectivity characteristics of the water body in different wave bands are used to construct a water quality inversion model, and water quality parameters such as chemical oxygen demand and ammonia nitrogen content are obtained by inversion, and the inversion results are classified according to the water quality standard to obtain the water quality index evaluation results. The reflectivity characteristics of the water body in different wave bands are used to construct a water quality inversion model, and water quality parameters such as chemical oxygen demand and ammonia nitrogen content are obtained by inversion, and the water quality index evaluation results are obtained by classification according to the water quality standard. This method realizes rapid and large-scale monitoring and evaluation of water quality parameters based on remote sensing images, without the need for a large number of field sampling, reduces the evaluation cost, and at the same time can reflect the spatial distribution difference of water quality, provides a scientific basis for mastering the overall water quality of the river and judging the degree of water pollution.

[0026] In the embodiment of the present application, the constructed evaluation model is a model combining analytic hierarchy process and fuzzy comprehensive evaluation method, wherein the analytic hierarchy process is used to determine the weight of each evaluation index, and the fuzzy comprehensive evaluation method is used to obtain the final river ecological environment quality evaluation result according to the index weight and the index evaluation result. The evaluation model combining analytic hierarchy process and fuzzy comprehensive evaluation method is constructed. The analytic hierarchy process divides the complex evaluation problem into different levels, compares each evaluation index with each other and assigns weights, so that the determination of index weight is more scientific and reasonable. The fuzzy comprehensive evaluation method can handle the uncertainty and fuzziness in the evaluation process, combine the evaluation results of each index with the weight, and obtain the final river ecological environment quality evaluation result. The combination of the two methods makes the evaluation process more systematic and objective, improves the accuracy and rationality of the evaluation result, and is more in line with the actual river ecological conditions.

[0027] In the embodiment of the present application, the step of verifying the evaluation result is specifically: The field monitoring data of the target river area is collected, and the field monitoring data is compared and analyzed with the evaluation result to verify the accuracy and reliability of the evaluation method. After the evaluation result is output, a step of generating a river ecological environment quality evaluation report according to the evaluation result is included. The evaluation report includes description of the current situation of the river ecological environment, analysis of existing problems and targeted protection and improvement suggestions.

[0028] The field monitoring data is collected and compared and analyzed with the evaluation result to verify the accuracy and reliability of the method. This step can find possible problems in the evaluation method and improve it, ensuring the effectiveness of the evaluation method and the credibility of the evaluation result. After the evaluation result is output, an evaluation report containing the description of the current situation of the river ecological environment, the analysis of existing problems and the targeted protection and improvement suggestions is generated. This report provides specific and operable guidance for the protection and management of the river ecological environment, so that relevant departments can develop reasonable protection and management measures according to the report to promote the improvement of the river ecological environment.

[0029] In summary, the river ecological environment quality evaluation method based on remote sensing image firstly acquires multi-source remote sensing image data of the target river region, which at least contains optical remote sensing image data containing green light, red light, near-infrared and short-wave infrared bands, and the spatial resolution is not less than 10 meters and the time resolution is not less than 15 days, and the radar remote sensing image data has a spatial resolution of not less than 30 meters and a time resolution of not less than 30 days; then the pre-processing is carried out, including the radiation correction of the optical remote sensing image by the radiative transfer equation method and the radar remote sensing image by the absolute calibration method, and the geometric correction and the atmospheric correction, to obtain the corrected image data; then the river width is extracted from the corrected image, the boundary is identified by the edge detection algorithm, and the vertical distance is calculated, the river length is calculated by the center line extraction algorithm, the water area, the water turbidity, the vegetation coverage, the land use type and other characteristic parameters are calculated; then the river ecological integrity index, the water quality index, the river bank stability index and other evaluation indexes are calculated according to these characteristic parameters; then the evaluation model is used to determine the index weight and the fuzzy comprehensive evaluation method is combined with the weight and the index result, the ecological environment quality of the target river region is evaluated and the result is output; finally, the accuracy and reliability are verified by comparing the field monitoring data with the evaluation result, and the evaluation report containing the ecological status description, the problem analysis and the protection improvement suggestion is generated according to the evaluation result.

[0030] Meanwhile, the contents not described in detail in the specification all belong to the prior art known by those skilled in the art.

[0031] It should be noted that, in this paper, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the term "include", "contain" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment.

[0032] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for evaluating river ecological environment quality based on remote sensing images, characterized in that: Specifically comprising the following steps: A1, acquiring multi-source remote sensing image data of a target river area, the multi-source remote sensing image data comprising at least optical remote sensing image data and radar remote sensing image data; A2, pre-processing the acquired multi-source remote sensing image data, the pre-processing comprising radiation correction, geometric correction and atmospheric correction to obtain corrected image data available for analysis; A3, extracting feature parameters related to river ecological environment from the corrected image data, the feature parameters comprising but not limited to river width, river length, water area, water turbidity, vegetation coverage and land use type; A4, calculating various indexes for evaluating river ecological environment quality according to the extracted feature parameters, the indexes comprising river ecological integrity index, water quality index and riparian zone stability index; A5, using a pre-constructed evaluation model, combining the calculated various indexes, evaluating the ecological environment quality of the target river area and outputting the evaluation result.

2. The river ecological environment quality assessment method based on remote sensing images according to claim 1, characterized in that: The remote sensing image data comprises green light band, red light band, near-infrared band and short-wave infrared band.

3. The river ecological environment quality assessment method based on remote sensing images according to claim 1, characterized in that: In the step of acquiring multi-source remote sensing image data of a target river area, the spatial resolution of the optical remote sensing image data is not less than 10 meters and the temporal resolution is not less than 15 days; the spatial resolution of the radar remote sensing image data is not less than 30 meters and the temporal resolution is not less than 30 days.

4. The river ecological environment quality assessment method based on remote sensing images according to claim 1, characterized in that: In the process of performing radiation correction on the acquired multi-source remote sensing image data, for the optical remote sensing image data, the radiation transfer equation method is used for correction; for the radar remote sensing image data, the absolute calibration method is used for correction.

5. The river ecological environment quality assessment method based on remote sensing images according to claim 1, characterized in that: The method for extracting river width from the corrected image data is: B1, using an edge detection algorithm to identify the river boundary and obtaining the river width by calculating the vertical distance between the river boundaries; B2, the method for extracting river length is: using a center line extraction algorithm to extract the center line of the identified river area and obtaining the river length by calculating the length of the center line. 6.The river ecological environment quality assessment method based on remote sensing images according to claim 1, characterized in that: When calculating the water quality index, a water quality inversion model is constructed using the reflectivity characteristics of the water body in different bands, water quality parameters such as chemical oxygen demand and ammonia nitrogen content are obtained by inversion, and the inversion results are classified according to the water quality standard to obtain the water quality index evaluation result.

7. The river ecological environment quality assessment method based on remote sensing images according to claim 1, characterized in that: The constructed evaluation model is a model combining analytic hierarchy process and fuzzy comprehensive evaluation method, wherein the analytic hierarchy process is used to determine the weight of each evaluation index, and the fuzzy comprehensive evaluation method is used to obtain the final river ecological environment quality evaluation result according to the index weight and the index evaluation result. 8.The river ecological environment quality assessment method based on remote sensing images according to claim 1, characterized in that: The step of verifying the evaluation result is specifically: Collecting field monitoring data of the target river area, comparing and analyzing the field monitoring data with the evaluation result, verifying the accuracy and reliability of the evaluation method, and after outputting the evaluation result, including the step of generating a river ecological environment quality evaluation report according to the evaluation result, the evaluation report comprising description of the current situation of river ecological environment, analysis of existing problems and targeted protection and improvement suggestions.

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