地形因子与DEM分辨率关系的初步研究——以蒙阴县为例

Research for the Influences of DEM Resolution on Topographical Factors——A Case Study of Mengyin County

以蒙阴县为研究区探讨坡度、坡长、坡向、汇水面积随DEM分辨率的变化。基于1∶5万地形图利用ANUDEM建立多种分辨率的DEM,分辨率水平包括10,15,20,25,30,40,50,75,100,150,200,250,300,400,500,750,1000 m,基于上述DEM提取坡度、坡长、坡向、汇水面积,探讨其随分辨率的变化规律。结果表明:随分辨率降低,平均坡度呈对数函数衰减,坡度向低坡度范围集中,平均坡长增大且在高分辨率范围内较剧烈,坡长向较长坡长范围集中,分辨率200 m以坡向统计信息受分辨率降低的影响小于10%,随DEM分辨率降低平均汇水面积呈线性增大,且不同汇水面积等级所占面积的变化规律不同。

The influnce of DEM resolution on four topographical factors including slope, slope length, as- pect and catchment area was analyzed by taking the county of Mengyin as research area. Topographical factors mentioned above were derived from DEMs with resolution of 10, 15, 20, 25, 30, 40, 50, 75, 100, 150, 200, 250, 300, 400, 500, 750, 1000 m based on the digital map （1 ： 50000） byANUDEM. Theresult showed that with DEM resolution reduction the average of slope decreased following logarithmic function, slope tended to be lower, slope length tended to be longer and the accretion of slope length is faster in higher resolution range, the impact of DEM resolution within 200 m on aspect is lower than 10%, the average catchment area becom larger following linear ruction and the changes of area for different range of catchment area are different.