An Extraction Algorithm of Digital Drainage Network from Digital Elevation Model

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.The paper has introduced the basic principle and calculated steps of the arithmetic model of D8,it also has included some questions about threshold setting of extracting drainage network.This article has simulated the Dagujia River network of Yantai city by using this model,and compared it with the actual river network.The results show that the algorithm in different basins should take a different threshold.The scope of the threshold affect the density and precision of the extracted network widely.Finally,the existing shortcomings of algorithms have been pointed out.