As one of basic parameters of gridded DEMs

resolution influences the quality of DEMs and t1 precision of terrain analysis.Choice of a suitable resolution is the basic problem to solve in generating at using DEMs.Based on the terrain features data with high precision of study area in northern Shaanxi Proince

which are extracted by the full digital photogrammetrv

9 source data with different data densities create DEMs are obtained.Two types of DEMs

i.e.

ANUDEM and TIN-DEM with different grid size are generated using the source data

and RMS slope

average slope and RMSE of elevation are extracted from the DEMs.According to the relationship between the grid size and RMS slope

average slope and RMSE elevation

a suitable resolution is achieved.Results show that the suitable resolution for building DEM 1 the full digital photogrammetrv is about 2.5 m in scale 1:10000.