Application research of unmanned aerial vehicle remote sensing detection for 3D terrain modeling and feature analysis of debris flow gullies in complex mountainous area of Dongchuan

Taking the debris flow gully of the tributary of the Dabaini River on the left bank of the middle reaches of the Xiaojiang River Basin in Dongchuan District, Yunnan Province as the research object, the surface landform data of the debris flow gully was collected by Unmanned Aerial Vehicle (UAV) remote sensing technology. This paper proposes a method of extracting the control points of the same-named objects in combination with the ground three-dimensional laser scanning modeling data to realize the absolute orientation of UAV image data. Through Smart3D image data processing, a three-dimensional terrain model of the study area is constructed to obtain digital orthophoto map (DOM), digital surface model (DSM) and high-density matching point cloud. The point cloud data is processed using the Irregular Triangle Network progressive encryption technology in PhotoScan software to obtain a digital elevation model (DEM) with a resolution of 0.5 m. Combined with the relevant terrain analysis modules in ArcGIS and Cloud Compare, the terrain characteristics of this section of debris flow valley area can be analyzed. The technical route and method used in the modeling and analysis of debris flow gully terrain based on UAV remote sensing are of important empirical case reference value and practical guiding significance for qualitative and quantitative detection of geological disasters in the plateau complex mountain area and their monitoring and prevention.