不同插值方法的栅格DEM质量分析与最佳分辨率的选取

Quality Analysis of Grid DEM of Different Interpolation Methods and Selection of Optimal Resolution

以鄱阳湖自然保护区为例,利用不同内插算法生成DEM,并选取高程差绝对值、中误差以及单点最大误差三大指标分析了DEM的精度,结果发现利用反距离加权(IDW)算法的精度较好。利用坡度中误差的大小判定了不同网格分辨率下的DEM精度,试图选取DEM的最佳分辨率,结果显示:当分辨率达到20时,坡度中误差的变化明显减缓,因此确定最佳分辨率为20。

To take the Poyang Lake natural reserve as an example, different interpolation algorithms were used for generating DEM. Three indexes, namely absolute elevation, mean square error and maximum error of single point, were selected to analyze the accuracy of DEM. The results revealed that using inverse distance weighting （IDW） algorithm had better accuracy. In order to se- lect the best DEM resolution, the slope mean square error was used to judge DEM precision under different grid resolutions. When the resolution reached 20, the changes in the slope mean square error decreased obviously. Thus, the best resolution was 20.