| Landslide geological disasters caused by heavy rainfall have the characteristics of sudden and sliding.Due to the limitation of weather,terrain and other conditions during the disaster period,the traditional manual survey can not be carried out at the first time,and can not meet the needs of disaster relief.Multi source remote sensing data make up for the defects of a single sensor.Relying on its advantages of large range,long time sequence and all-weather real-time imaging,it can quickly extract all kinds of evaluation factors in the research area.On this basis,the comprehensive evaluation results are obtained by analyzing all kinds of evaluation factors based on GIS platform statistical tools and information model,which can provide timely data support for disaster relief planning and disaster prevention measures.Based on the national key R &D program of environmental elements emergency and monitoring coupling application demonstration support,this paper applies domestic satellite data to overseas demonstration areas.Taking the landslide geological disaster in Sri Lanka in May 2017 as the research object,the multi-source remote sensing image data collected by GF-3,sentinel,Landsat and MODIS series satellites are used to extract the information of various evaluation factors in the study area,and the information model of GIS platform is used to evaluate the susceptibility of landslide geological disaster in the study area(1)This paper introduces the advantages of multi-source remote sensing data in landslide geological hazard research compared with traditional manual investigation.The characteristics of the satellite data collected in this paper are described in detail,and a set of normalization preprocessing process of multi-source image data is established.The collection of multi-source data makes up for the defect of a single sensor,which can extract all kinds of evaluation factor data in the study area at the first time.(2)It is difficult to get the optical image because of the extreme weather.Based on the advantages of all-weather multi polarization of GF-3 microwave remote sensing image and the data of Geological Survey Bureau combined with the imaging characteristics of microwave remote sensing image,this paper establishes the interpretation mark of landslide.With the help of sentinel-2 optical image,the landslide disaster points in the study area are interpreted by remote sensing.A total of 408 landslide disaster points were interpreted and their scale was counted.(3)By analyzing the formation mechanism of landslide disaster and combining with the environmental characteristics of the study area,the evaluation index system of landslide disaster susceptibility in the study area is established.According to the index system,eight evaluation factors which have great influence on landslide formation are selected,and the eight evaluation factors selected through the index system are extracted and quantified by using the multi-source remote sensing image data of each satellite.(4)The correlation between the pixel number and density of some disaster points and the layers of evaluation factors was analyzed.The GIS information model is introduced to calculate the information value of each evaluation factor and superimpose to generate the comprehensive information value of the study area.The natural breakpoint method is used to generate the comprehensive information value,and the regional landslide hazard susceptibility zoning is studied.The evaluation results show that the high and medium risk areas are mostly distributed by ridge,showing a strip shape,and its formation is closely related to terrain,vegetation type and soil type.According to the superposition statistics of the zoning results and the disaster points not involved in the analysis,97.53% of the disaster points are located in the medium and high risk areas,which is basically consistent with the distribution of geological disaster points,and has a certain utilization value. |
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