SRTM1 DEM与ASTER GDEM V2数据的对比分析

本文以山西省为实验区,基于ICESat/GLA14测高数据对SRTM1 DEM和ASTER GDEM V2数据的垂直精度进行了对比,分析了其在坡度、土地利用类型和地貌类型中的误差分布情况,并基于地形剖面方法分析了2种DEM数据在地形表达上的差异。研究结果表明：① 在垂直精度上,SRTM1 DEM数据要明显高于ASTER GDEM V2数据,其绝对误差均值分别为4.0 m和7.8 m,标准偏差分别为6.0 m和10.7 m,均方根误差分别为6.1 m和10.7 m。② 这2种DEM数据的精度受坡度影响严重,随坡度值的升高误差增大;SRTM1 DEM的绝对误差均值、标准偏差和均方根误差在水田最小,在林地最大,而ASTER GDEM V2的这3种误差在居民用地最小,在林地最大;SRTM1 DEM 和ASTER GDEM V2的绝对误差均值、标准偏差和均方根误差在平原地区最小,在大起伏山地最大。③ 在平原和台地地区,ASTER GDEM V2数据高程值有异常波动,SRTM1 DEM在起伏山地存在对山谷过高估计。总体上,SRTM1 DEM比ASTER GDEM V2对地形的表达准确,与ICESat/GLA14对地形的描述基本相一致。

Analysis and Comparison of SRTM1 DEM and ASTER GDEM V2 Data

Taking Shanxi Province as the research area, this paper compared the vertical accuracy of SRTM1 DEM and ASTER GDEM V2 data based on ICESat/GLA14 altimetry data. Firstly, error values for these two DEM datasets were acquired by taking ICESat/GLA14 data as the real data, and their error parameters were also calculated, such as mean error (ME), absolute mean error (AME), standard deviation (STD) and root mean square error (RMSE). Then, the error distribution of these two DEM datasets were analysed within the classes of slope, land use type and landform type. Finally, based on topographic profile method, the vertical error differences between these two DEM datasets in topographic types were analysed. The research results showed: (1) The vertical accuracy of SRTM1 DEM data is significantly higher than that of ASTER GDEM V2 data. The RMSE values of SRTM1 DEM and ASTER GDEM V2 are 6.1 m and 10.7 m, respectively. (2) Error analysis based on slope factor showed that the vertical accuracy of these two DEM datasets is affected seriously by the slope, and the error value increases with the increase of the slope value. Error analysis based on land use factor showed that the AME, STD and RMSE values of SRTM1 DEM are the lowest in paddy field, the highest in forestland, and the three error parameters of ASTER GDEM V2 are the lowest in building and the highest in forestland. Error analysis based on landform type factor showed that the AME, STD and RMSE values of SRTM1 DEM and ASTER GDEM V2 data are the lowest in the plain area, and the highest in large fluctuation mountain area. (3) On the selected topographic profiles in plain and terrace areas, the elevation value of ASTER GDEM V2 data have abnormal fluctuations. SRTM1 DEM data is too high for the estimation of valley. Overall, SRTM1 DEM is more accurate than ASTER GDEM V2 for terrain representation, which is basically consistent with ICESat/GLA14.