Research On The Extraction Method Of Debris Flow Information In Dongchuan District Based On Gaofen-2 Satellite Image

China is a country with frequent geological disasters.The mudslides in Dongchuan District are widely distributed,frequent,erupting,serious,and complete in type.It is one of the most frequent occurrences of mudslides in the country,and the occurrence of mudslides in Dongchuan District.Lightly destroying the road,normal traffic,and destruction of the building,causing the disappearance and casualties of personnel.With the rapid development of domestic high-resolution satellite imagery,it plays an increasingly important role in geological disaster investigation.The high-scoring satellite 2 is the first civilian remote sensing satellite developed by China with a spatial resolution better than 1 meter.It has the characteristics of high positioning accuracy,high radiation accuracy and strong maneuverability.It provides reliable basic data for the investigation and monitoring of geological disasters,which plays an important role in the investigation of debris flow hazards.The paper studies the application of high score satellite image data in the automatic extraction of debris flow.According to the characteristics of debris flow development,using the spectral characteristics of debris flow on the high-resolution satellite imagery,the vegetation index(NDVI),soil brightness index(NDSI)and the first principal component obtained by principal component transformation were selected(PC1).Three related factors are used to study the development of debris flow,and the debris flow area is automatically segmented by selecting appropriate thresholds.Secondly,according to the DEM data of the study area,the valley valley automatic extraction algorithm is used to extract the valley range;finally,the research area DEM Slope extraction and sub-basin division are performed to assist in screening the debris flow area,and finally determine the debris flow area range.Taking the high-scoring satellite imagery and ASTER GDEM V2 data as an example,the paper extracts the debris flow area in the study area and finally extracts 38 debris flow maps.In order to verify the accuracy of automatic extraction of debris flow areas,visual interpretation of the study area images was performed.Firstly,the processing of highresolution satellite image data is studied.According to the processed image data and the spectral characteristics of the debris flow in the study area on the high-resolution satellite imagery,the corresponding interpretation marks are established and interpreted.43 mudslides in the study area.The results of the automatically extracted mudslide flow and the visually interpreted debris flow are compared and verified.The automatically extracted debris flow map and the visually interpreted debris flow map have 29 debris flow boundary ranges.The extraction accuracy of the coincidence reached 67.44%,and the extraction results were analyzed.Through the comparative analysis of the results,it is concluded that the automatic extraction method of debris flow information designed in this paper is feasible,and good debris flow extraction effect can be obtained.Finally,a brief analysis of the spatial distribution characteristics of debris flow is made.