中文摘要：

SRTMDEM和ASTERGDEM数据作为目前全球最完整的高精度地形数据,自发布以来,就一直是全球范围内应用最为广泛的DEM数据,其精度评价问题也是历来研究的焦点。但目前研究多集中在中小区域或典型地形区,且多以DEM高程数据精度分析为主,缺乏误差空间分布规律的探究。该文以中国大陆为研究区域,以GLA14点数据为参考高程,研究两类DEM的误差统计特征和空间分布特征。研究表明:SRTMDEM和ASTERGDEM在我国的精度稍优于标称精度,但整体上存在约1m的系统性误差;SRTMDEM误差在平坦区域呈菱形分布,而在地势复杂区域,误差与地形具有较强的相关性;ASTERGDEM误差呈明显的条带状分布且误差正负值间隔分布,条带方向为东北-西南方向,与SRTMDEM相比,ASTERGDEM受地形影响较小。研究结论对两类DEM的应用、融合等研究有着一定的参考价值。

英文摘要：

As a kind of terrain data,SRTM DEM and ASTER GDEM have the complete coverage at globe scale with relative high accuracy.Since their publication,these two datasets have been widely used in the researches at global scale,and their accu-racy assessments have also been the research focus consistently.However,current studies tend to ct^nverge on middle and small scaleareas or typically morphologic regions.In addition,more attentions have been paid to the accuracy analysis of DEM data,which lacking of the researches on error spatial distribution.Referring to GLA14data,this paper investigates the statistical and spatial distribution characteristics of the errors of the two DEM datasets,and the study area covers the whole Chinese mainland.In general,several conclusions can be achieved:As to statistical characteristics,the accuracies of SRTM DEM and ASTER GDEM in the study area are slightly better than their nominal precision,but the systematic error is about1meter as a whole.As to the spatial distribution characteristics,the SRT M DEM errors present a diamond shaped distribution in flat areas,while the errors have a strong correlation with the topography in(mmplex terrain areas.As a contrast,the AST ER GDEM errors present a band shaped distribution at northeast southwest direction,with the positive and negative values distributing at intervals,and has a weak correlation with the topography.To sum up,the research results have a certain reference value for the study of the two DEM data applications and their fusion researches.