ANALYSIS AND COMPARISON OF SRTM3 DEM AND ASTER GDEM V2

Abstract. Global Geographic Information Resources Construction and Maintenance Renewal Project is in urgent need of digital elevation model worldwide. At present, the errors of ASTER GDEMv2 and SRTM3 DEM data widely used are unevenly distributed. In this paper, high-precision and high-resolution WorldDEM data are taken as true values, and flat areas in Turkey and alpine region in Nepal are selected respectively as two test areas A and B. The vertical accuracy of ASTER GDEMv2 and SRTM3 DEM data is verified and compared by using DEM elevation difference numerical analysis, spatial differentiation analysis, slope spectrum curve and other methods. The results show that the two digital elevation models in flat terrain conform to the nominal accuracy, and the vertical accuracy of SRTM3 DEM has an advantage, while the vertical accuracy of ASTER GDEMv2 in high elevation area with large terrain fluctuation is obviously higher than that of SRTM3 DEM , and the area of SRTM3 DEM data accuracy exceeding nominal accuracy is larger. On this basis, the applicability of the two kinds of DEM is analyzed. It is concluded that SRTM3 DEM data with better accuracy should be selected in low altitude plain areas, ASTER GDEM data with higher resolution should be given priority in hilly areas with complex terrain and high mountain areas with severe topographic fluctuations, and ASTER GDEM data can be used to supplement the uncovered areas of SRTM3 DEM。In addition, in areas with high vegetation coverage, the accuracy of the two data is greatly affected, which can be supplemented by ICESAT/GLAS and ICESAT2/GLAS data with strong vegetation penetration ability. The results can provide scientific basis and data support for global space information projects.