DEM地形信息提取对比研究--以坡度为例

Comparison of landform information extracted from DEMs-A case study of slope

由于DEM数据本身多尺度因素,加之地形、地貌特征具有宏观性与区域分异性的特点,直接的信息提取往往很难达到预期的目的。利用DEM制作坡度图高效、省力,但其精度有很大的不确定性,同时DEM制作过程中的误差传播、转移对坡度信息的影响缺少系统的判断依据。选取位于陕北黄土高原上的两个不同地区作为实验样区,在不同DEM生产的基础上,以高精度的1∶10 000DEM为准值,通过对1∶5万和1∶1万DEM提取定量地形要素的叠合、比较与统计分析,探讨具有不同地貌类型的区域1∶5万DEM提取地形信息的精度及其统计意义上的数量百分比关系。

With regional variation and macroseope of landforms, it is much more difficult to extract information from multiscale DEM data. As a result the information, which was extracted directly from DEMs, could hardly satisfy our aims. Using DEM to drive slope could save time and labor, but its precision is very uncertain. There was a lack of systematic standard for judging the error propagation and transformation, which has come along the production. This research chose two different regions （loess plateau of North Shaanxi Province） as test areas. Based on different DEM production process and took the 1 ： 10000 scale DEM as true value, we superposed, compared and statistically analysed the qualitative landform information, which were extracted separately from 1 ： 50000 and 1 ： 10000 scale DEMs. Then based on statistical values of terrain information derived from the 1 ： 50000 DEM, the paper discussed the accuracy, as well as the quantity relation between different landforms. The outcome of this study will be useful for the application of larger scale DEMs.