Study on Accuracy of GTOPO30 and SRTM DEM——A Case Study of Tibet

Topographic data are critical to global changes in climate,land formations,atmospheric changes,and research in soil and water loss.Recently,NASA released SRTM DEM at 90-meter resolution covering 80 % of the Earth's land surface.Prior to SRTM DEM,GTOPO30 (1 km) was the highest-resolution global DEM.As it is a new product,we have no knowledge of SRTM DEM,and so,it is necessary to assess its accuracy.The article in- troduces apparent accuracy and production procedure of SRTM DEM in comparison with GTOPO30.Further- more,the article analyzes and compares these two DEM datasets at 1 km resolution in Tibet.Results show that SRTM DEM has higher accuracy than GTOPO30.This research can be a good reference for applications in other areas.