Research and application on digital river network extraction modified routing algorithm based on DEM

Extracting the hydrological and terrain parameters based on Digital Elevation Model (DEM) is the foundation of distributed hydrological model of basin space discrete analysis and application of integrated Geographic Information System (GIS). Based on the data independence assessment of DEM, a modified algorithm applied to flow-routing, which is one important step of river network extraction is presented. The Specific Contributing Area (SCA) is set as the calculated objective to be compared. A simulation to actual terrain and the theoretical value of SCA are given and compared with the computational results of flow-routing algorithm. This paper mainly presents the superiority and inferiority of D8 and represents an improved method of D8. Finished the application study of the Changhu irrigation district in Sichuan province and got a satisfied result. The results show that the algorithm has a higher degree of automatic extraction and a certain value in the analysis of river network structure.