黄土丘陵沟壑区1∶1万及1∶5万比例尺DEM地形信息容量对比

A Comparison on Digital Terrain Models of Different Scales in Loess Hill and Gully Area

黄土丘陵沟壑区地形变化异常复杂 ,1∶5万地形图对原始 1∶1万地形图等高线形态综合、取舍程度很大 ,这些都在不同程度上影响了地形分析结果的准确性。以高精度的 1∶1万比例尺DEM为校准值 ,运用 1∶1万及 1∶5万比例尺DEM叠合比较分析的方法 ,研究 1∶5万DEM的地形信息容量及提取不同地形要素的精度。试验结果表明 ,在黄土丘陵区 ,与 1∶1万DEM相比 ,1∶5万DEM在所提取的地面坡度、地面曲率、沟壑量等地形定量指标方面均都存在着较大的误差。

Taking Jiuyuan valley in the loess hill and gully area as a test site, the accuracy of terrain variables derived from 1∶50 000 scaled DEMs by means of a careful comparison with high accuracy DEMs of 1∶10 000 scaled is probed into. The experiment shows a big error between the terrain variables(i.e. slope gradient, surface curvature, channel networks etc.) derived from the both information sources. At present, 1∶50 000 scaled DEM has been set up in the whole country, which will be applied as an important base for soil erosion investigation as well as soil and water conservation project planning in the loess plateau region.