Research on River Networks Extraction Based on RS and GIS

In view of the arid and semi-arid situation in most areas of Longchuan river basin, it is helpful to study the hydrological characteristics of the watershed to alleviate the drought situation in the region. Through the GDEM image provided by ASTER sensor carried by Terra satellite, the DEM data is preprocessed in GIS, the automatic extraction of river network, channel classification and sub-basin division are realized. The method of calculating the inflection point of the curve of the confluence accumulation and the density of the river network is used to determine the threshold value, and finally the river network water system which is consistent with the actual river is extracted.