Abstract:Digital Elevation Model(DEM)is the essential data for research on Terrain and SRTM data are the public free access dataset with 90 m resolution.Topographic representations of SR TM and DEMs generated from 1∶50 000,1∶100000,and 1∶250 000 topographic map sare compared and the surface and derived topographic parameters including slope,curvature,streams,and slope length are ext racted.Results show that SR TM data p resent less terrain details on the table capacity than the 1∶50000 topographical map,even not better than the 1∶10000 topographic map,but better than the 1∶250000 TINDEM.