The algorithm design and optimization for water erosion topographic factors based on digital elevation model

It is significant for water erosion survey and prediction to compute the water erosion topographic factors, which consist of slope angle and slope length factors. Based on the theories of slope hydrology, soil erosion, the analysis of digital terrain, and the arithmetic of multiple flow direction, the principle and achievement of an improved and optimized arithmetic for the terrain factors extraction form Digital Elevation Model are expounded. By taking the area of Hilly Loess Plateau in northern Shaanxi as an example, the water erosion terrain factors are extracted with this optimized algorithm. And with the spatial structure and spatial statistic analysis, this algorithm is verified as reasonable and stable, meanwhile, it resolves the discontinuity in the raster surface of the slope angle and slope length factors derives from the old methods, which have a continuous raster surface and in according with the origin DEM surface.