适于大规模地形分析的计算格网应用

GRID Services for Large Scale Elevation Derivatives Computation

摘总结前人在GIS领域应用格网的理论和实验基础上,使用Globus Toolkit 3构建DEM计算地形因子的格网服务(CSED),适用于大洲规模的DEM地形分析,并能够通过Web发布计算结果。基于此格网系统,进行了Shuttle Radar Topography Mission(SRTM)数据在地形因子自动化提取方面的计算实验。这些计算由于依赖的计算环境的重大变化,所体现出来的效率性能等方面有了很大的变化。本文选取中国青藏地区的地形数据进行了详细试验,并对实验区数据和GTOPO30的计算结果进行了对比分析。

Analysis of automatically extracting terrain features based on Digital Elevation Model （DEM） such as slope gradient, slope aspect, curvature, flow paths and delineate drainage networks, is always a kind of fundamental work for many geoscientists. Shuttle Radar Topography Mission （SRTM）, which produced a near global scope database of high accuracy elevation data, offers an opportunity to extend terrain analysis from local to global. However, it is a major disincentive for geoscientist to deal with massive DEM data even in a limited interesting research area. Grid Services for Elevation Derivatives （GSED） is proposed for spatial data dissemination and continental-scale topographic analysis computation based on DEM. The architecture of GSED is presented in the paper and unique problems that appear in the computing test are elaborated. Automation topographic factor extraction from SRTM is carried out reorganized through GSED. Traditional sequential algorithm has been to adapt to the distributed computing environment. Tibetan Plateau is selected as the focus area, and preliminary result is established for comparison with GTOPO30. The result confirms that GSED is an effective method to solve the problem of high throughput computation with large scale geographic data.