Elevation Quality Evaluation Of SRTM3DEM And ASTER GDEM Data In China

SRTM DEM (Shuttle radar topography mission digital elevation model) is a radar image data which covering more than80%of the Earth’s land surface, ASTER GDEM (Advanced Spaceborne Thermal Emission and Reflection Radiometer Globe digital elevation model) is a near-infrared image data which covering more than99%of the Earth’s land surface.The two data can provide users in the all World with the most complete and free global digital elevation data. What’s more,the two data has gradually become an important source of data of the field of scientific research and application of digital elevation model.However, China has not yet nationwide SRTM3DEM and ASTER GDEM elevation quality evaluation until now.This paper selects typical test area and treat the state1:50000DEM which provided by National fundamental geographic information database as reference contrastive data and compares SRTM3DEM data with the1:100000DEM and the1:250000DEM, using DEM polygon error visual analysis, Spectrum of polygon error, polygon error information entropy model, Mean Square Error model to quantitative analysis the SRTM3DEM elevation accuracy of China and the ASTER GDEM elevation accuracy of eastern region of China. The results show that:(1) China’s Taihu drainage basin SRTM3DEM ploygon error increases with the study area elevation increased and the complexity of the terrain structure, the elevation accuracy of SRTM3DEM are better than the1:250000DEM but worse than1:100000DEM. DEM polygon error map can describe the trend of mountain ridge lines and valley lines in the case Grade1m.(2) Nationwide SRTM3DEM data elevation quality evaluation research showed the elevation quality evaluation of SRTM3DEM affected by topography and presence of some spatial difference. The elevation accuracy quality of SRTM3DEM is better than1:250000DEM in the all terrain in Zhejiang region. At the same time, SRTM3DEM data elevation quality evaluation affected by topography in Xinjiang、Liaoning、 Shandong、Hainan region. In the study area, the elevation accuracy quality of SRTM3DEM is better than1:250000DEM in the hilly and mountain terrain, however the elevation accuracy quality of1:250000DEM is better than SRTM3DEM in the plain terrain.(3) China’s eastern region ASTER GDEM data elevation quality evaluation research showed the elevation accuracy quality of ASTER GDEM is better than SRTM3DEM and1:250000DEM in the in the hilly and mountain terrain. The study also considered Whether the ASTER GDEM data elevation error across the map is uniform distribution or not has non-decision relationship with the data height accuracy quality level.At the same time the study also found that the DEM polygon error mathematical expectation could help visibility analysis of the DEM polygon error.