最佳DEM分辨率的确定及其验证分析

Identifying the optimal DEM resolutions and analyses of simulation results

在玛尔挡地区格网DEM的数据上选择实验样区,以不同分辨率情况下DEM数据对地表模拟表达的逼近程度为研究对象,最优逼近时的栅格单元大小的临界值就是所求的最佳分辨率。在分析坡度中误差法和公式法等常见方法的基础上,借鉴坡度中误差的思想,选取区域地形粗糙度K、剖面线长度SL两个定量指标来综合分析确定该地区格网DEM的最佳分辨率。在ArcGIS平台上对方法进行了实验验证,得出分别以2m和8m作为玛尔挡地区1∶10 000和1∶50 000 DEM生产时是最佳分辨率的结论。研究表明这种解决办法不仅可以克服GIS空间分析中DEM分辨率确定的盲目性和随意性,而且能确保基于DEM的各种空间分析的精度,为相关研究提供重要的参考价值。

This paper selected the experimental region from the grid DEM of Maerdang region, and the research object is the like- ness-degree of simulating real ground surface under the condition of different DEM resolution data. The optimal grid size is the so called optimal DEM resolutions here. By the thought of gradient root-mean-square error （ RMS error） , selected the terrain roughness K ＆ pro- file length SL two quantitative indicators to conclude the optimal DEM resolutions at Maerdang hydropower after analyzing with the nor- mal methods of RMS method and Formula method. It concluded that the optimal resolutions of Maerdang region DEM data is 2m on the condition of 1：10 000 and 8m on the condition of 1：50 000. The study showed that such a solution could not only overcome the blindness and randomness in the determination of DEM resolution by GIS spatial analysis, but also ensure the accuracy of various space ana- lyses based on DEM, which could provide important reference value for those related studies.