数字地形模型数据产品特点 与评估分析

数字高程模型是支撑地理过程模型研究的重要基础数据。DEM数据获取、加工及压缩精度直接影响地学相关模型及地理过程的模拟效果和研究质量。在分析比较当今国际地学界应用DEM数据源的基础上，我们采用绝对差值法和三维剖面法对国家基础地理信息中心生产的基于1：50,000扫描地形图DEM产品(NFGIS_DEM)、GTOPO30_DEM数据及基于SRTM数据生产的DEM数据集进行了精度检验及评估。同时分析了影响由SRTM数据所生产的全球范围DEM数据集精度与数据质量。研究结果表明30-90m分辨率的SRTM_DEM产品在精度和数据质量控制方面远优于GTOPO30_DEM数据，与NFGIS_DEM数据质量相当。大范围乃至全球范围的30m分辨率SRTM_DEM产品，将极大促进基于DEM数据的地理过程模型的研究，尤其会大幅提升对DEM空间分辨率较敏感的地学相关研究能力。

A Characteristics and Assessment Analysis of DEM Products

Digital elevation model (DEM) is a digital model-building process of terrain relief. DEM is an important data set in sustaining geographical process model research. The DEM precision of acquiring, operation and compression would influence the simulation effect and research quality of relative Geo-models directly. In this paper, several DEM datasets had been analyzed and compared, which are used abroad in the international geographical society. 3D profile and check-point methods were applied in the research to complete the precision verifying and appraising of the three main DEM datasets, which are GTOP030 DEM data with 30 arc resolution, SRTM DEM with 90m resolution and the DEM with 25m resolution produced by national foundational geographical information center. Based on the comparison, the main factors effecting the precision and the quality of SRTM_DEM are discussed. The results indicate that, in the indexes of extremum, mean and std. variance, SRTM_DEM is two times as well as GTOP030_DEM. SRTM_DEM has better data quality control in the difference value as compared to NFGIS_DEM, and SRTM_DEM also has the mean absolute value about 0.3m (ie. SRTM_DEM has a higher confidence level in the general quality). The precision of SRTM_DEM has a great predominance in the geographical process model research, especially for the relative research ability sensitive to the spatial resolution of DEM.