DEM内插算法对区域坡长提取的影响分析——以陕北黄土丘陵区为例

利用陕北黄土丘陵区10m分辨率的高程数据,在Visual Studio平台下,实现双线性内插、反距离加权内插以及移动曲面拟合这三种DEM内插算法,进而对不同的内插DEM采用多流向算法实现坡长提取,最后对不同内插DEM提取的坡长进行空间结构分析、坡长精度分析、栅格坡长值的空间统计分析以及不同分辨率下(10m,25m,50m)不同内插算法坡长提取的比较分析。分析结果表明:(1)移动曲面拟合内插DEM生成的栅格坡长表面可正确表达各层级径流线信息,并具有与原始DEM以及坡度图相同的空间结构特征即表面的光滑连续特性,且其坡长提取精度最高,是适用于陕北黄土丘陵区域坡长提取的DEM内插算法;(2)空间统计分析表明,在实验区域内,不同内插算法在坡长值较小区域有显著性差异;(3)不同分辨率比较分析表明,在陕北黄土丘陵区域,不同分辨率对不同内插DEM坡长提取无显著性影响,且验证了分辨率越低坡长提取值越大的规律。

Effect of DEM interpolation on the slope length extraction

Based on the elevation data of 25m resolution of Northern Shaanxi's loess hilly region,three major interpolation algorithms,dual-linear,inverse distance weighted and moving fitting,were realized at the flat of Visual Studio.Furthermore,the DEM's slope length was extracted with the method of Multi-flow(MFD) at the same flat.Finally,with the analysis of to slope length surface structure comparison,slope length accuracy analysis,the values of the slope length statistics and comparative analysis of different resolutions of 10m,25m and 50m,under the same slope length extraction way by different interpolation methods,it was showed that the moving fitting interpolation algorithm is the most suitable interpolation method for slope length extraction of the three major DEM interpolation algorithms for the region of Shaanxi's loess hilly,because it produces continuous and smooth spatial surface,presents the small tributary more clearly than other interpolation methods.Moreover,it has the highest accuracy for extracting the slope length;By the values of slope length statistics,the three interpolation algorithms have obvious differences at the low value.Under different resolutions of the origin DEM,the three major interpolation algorithms do not have significant effect on the slope length extraction,and verified the rule that the lower of the DEM's resolutionis the higher of the slope lengthis.