关键词: 地形因子提取, 数字高程模型, 坡度坡长因子, 流域八叉树结构, 效率优化

Abstract: Topography is an important factor affecting soil erosion, which is usually measured by slope gradient and slope length in the estimation model. Topographic factors can be extracted by using DEM on regional scale. With the improvement of DEM data accuracy and the increase of data, the computing capacity for large amounts data has become the constraint on the topographic factor extraction on regional scale. To improve the efficiency of topographic factor extraction, the flow path was recorded and the integrated extraction process for flow direction, catchment and slope length were constructed by watershed octree. The experiment results indicated that this method could significantly reduce the redundant traversal and simplify the calculation. Compared with the traditional scanning traversal method, this method has higher accuracy and computational efficiency.

Key words: topographic factors extraction method, Digital Elevation Model(DEM), slope length and slope steepness factor(LS factor), watershed octree, efficiency optimization;