Abstract: It is a highly efficient method to acquire the information of stream network from DEM by using the arithmetic of D8,which is one of the most widely used models in extracting digital network.This article has simulated the stream network of Nanchuan city by using this model,and compared it with the actual river network.The study shows that exploring a method of simulate digital network by correlation analysis of choosing an appropriate threshold will make the generated network match up to the actual river muc...