多尺度DEM提取地势起伏度的对比分析——以福建低山丘陵区为例

坡度和起伏度是地形描述中最常用的参数,它们能快速、直观地反映地势起伏特征;坡度是划分平原和非平原的重要依据之一,地势起伏度可进一步划分台地、丘陵、小起伏山地、中起伏山地和大起伏山地等类型,基本地貌类型就是由海拔和起伏度两个指标确定的形态类型,它是遥感解译划分更详细地貌类型的基础。本研究以福建省1∶25万和1∶10万的DEM为实验数据,计算坡度划分平原和山地大区,其临界坡度值约为3°;利用ArcG IS空间分析中栅格窗口递增方法,对应不同尺度的DEM,计算地势起伏度,确定研究区的最佳分析窗口面积为4.41km²,得出中国低山丘陵区计算基本地貌形态类型的最佳尺度DEM为1∶25万比例尺,而1∶10万比例尺DEM适用于没有连绵起伏的更小范围的低山丘陵区;利用已有研究成果得出不同尺度DEM计算地势起伏度与最佳格网单元之间的函数关系。该研究对提取我国低山丘陵区基本地貌形态类型具有一定的借鉴作用。

A Comparative Analysis of the Multi-criteria DEM Extracted Relief Taking Fujian Low Mountainous Region as an Example

The slope and relief are commonly used parameters in describing terrain.In the regional study,using the DEM data to draw relief can reflect the terrain characteristics fast and directly.The slope is mainly used to divide plain and mountain region,and the relief is mainly used to sub-divide the hills,small rolling mountain,middle rolling mountain and the great rolling mountain.The basic landform type is determined by criteria of relief and elevation,and it is also the foundation of division for more detailed landform classification by remote sensing.In this article,with DEM data including 1∶250 000 and 1∶100 000 of the study area,the slope is calculated to draw up plain and mountain region with a critical slope value of being approximately 3°;using the method of increasing grid window progressively in ArcGIS space analysis,which corresponds to different DEMS,the relief is calculated to determine the best window area which is set to be 4.41km²;and using statistical method based upon comparison several different measures of the existing research results,the functional map of the study area between relief and the best window area is worked out.This research has certain model function when extracting the basic landform type in low mountain and hilly regions.