基于低空摄影高精度数字高程模型(DEM)的风沙草滩特征及稳定性评价

Feature Extraction and Stability Evaluation of Windy Sand Beach Area Based on High-resolution DEM with Low Altitude Aerial Photography

基于无人机低空摄影测量获取到的高分辨率数字正射影像图/数字高程模型(DOM/DEM),选取榆林榆阳区岔河则乡附近一片较为典型的风沙草滩为研究区,分别对沙丘地形因子(坡度、地形起伏度、地表粗糙度、剖面曲率)、斑块形状指数及植被覆盖度进行提取并构建稳定性评价体系,然后利用GIS空间分析功能对该区域内的沙丘稳定性进行了评价。结果表明:(1)无人机航测以便捷高效的特点,可生成高精度地形数据并实现小尺度沙丘地形特征提取;(2)在人工飞播固沙和风沙缓慢侵蚀的双重作用下,研究区已体现出较为稳定的风沙草滩区特有地貌环境特征;(3)该区域已经拥有一定程度的抵抗力稳定性,但不具备恢复力稳定性。

Based on the high resolution DOM/DEM obtained by UAV low-altitude photogrammetry, a typical sandy grass shoal area near Cha Heze town, Yuyang District, Yulin is regarded as the study area. Terrain factors(slope, relief, surface roughness and profile curvature), patch shape index and vegetation coverage of the dune are extracted, and the evaluation system is constructed. The stability of sand dunes in the region is evaluated by using GIS spatial analysis function. The results show that:(1) With convenient and efficient characteristics, UAV aerial survey can establish high precision terrain data and realize extraction of terrain feature of small scale sand dune.(2) Under the dual functions of artificial aerial seeding and slow erosion of wind-blown sand, this region has already reflected unique geomorphological characteristic of relatively stable wind-sand grass area.