DEM提取坡度·坡向算法的对比研究

以1∶1万地形图数字化所生成的DEM为研究对象,采用6种算法分别提取坡度、坡向。通过比较不同算法所提取坡度的平均值、最大值、标准差、中误差以及坡向的标准差、变异系数、坡向余弦中误差及标准差、不同坡向面积数据,定量地分析中误差与地形变化的关系,找到研究区较合理的坡度、坡向的提取算法,进一步分析不同水平分辨率DEM所提取的坡度、坡向的面积误差变化规律。运用面积百分比加权总体误差和面积百分比平均总体误差的指标,获取2项指标与水平分辨率的线性函数关系,为实际工作选取适宜的水平分辨率提供依据。

Algorithm Comparison of Slope and Aspect from DEM

The slope and aspect were extracted by 6 different algorithms based on DEM,which was produced by digitalizing the relief map with map scaled at 1∶10 000.By comparing mean value,maximum value,standard deviation,median error of slope and standard deviation,coefficient of variation,cosine median error and area data of aspects,analyzing the relationship between errors and terrain change,a reasonable algorithm of extracting slope and aspect was found.Furthermore,area errors,change regularity of slope and aspect based on different resolution DEM was analyzed.The indices of the total error of weighted area percentage and total error of average area percentage were used for obtaining the linear relationship between two indices and horizontal resolutions.The study aimed at providing some basis for choosing the approximate horizontal resolutions and it was meaningful for cost saving and decreasing the data amount at the condition of accuracy assuredness.