Research on Extraction of Watershed River Network Based on DEM Enhanced by Digital River System

According to the basic method for extracting the river channel network of watershed based on DEM and taking the digital river system’s catchment properties as controlling factors,the DEM values of main river channels are revised.In addition,the different DEM-based river network is extracted by varying catchment area threshold.At the same time,based on the relation of the river network density and catchment area threshold,the method of change-point analysis is used to produce an ideal catchment area threshold.The results show that the river network watershed extracted by this method would fit well with the actual river system.