基于ASTER GDEM和均值变点分析的中国东北地形起伏度研究

Analysis on the relief amplitude in Northeast China based on ASTER GDEM and mean change point method

地形起伏度是指某一确定区域内最高点和最低点之间的高差,是宏观尺度上比较适宜的地形分析指标,而确定最佳统计单元的大小是提取地形起伏度的关键。本文以中国东北地区为研究区域,以ASTER GDEMv2为数据源,基于Python模块编程,利用窗口分析方法依次提取n×n(n=2,3,4,……,198,199,200)网格下的地形起伏度,然后采用均值变点分析方法计算平均地形起伏度的最佳统计单元大小,最后将东北地区的地形起伏度进行分级。研究结果表明:1)通过Python模块编程可以实现提取地形起伏度的自动化运行;2)均值变点分析方法能够有效得检测出平均地形起伏度与网格面积拟合曲线上由陡变缓的拐点,利用该方法得到基于ASTER GDEM提取中国东北地区地形起伏度的最佳统计单元面积为2.62km2;3)东北地区整体起伏不大,以小起伏和微起伏为主,山地多为中小起伏。

Relief Amplitude is an appropriate terrain analysis indicator on a macroscopic scale,and determining the best statistical unit size is the key to extract the relief amplitude. Based on ASTER GDEM and Python module programming,the relief amplitude in the Northeast China was extracted with increasing grid window method at different windows（ 2 × 2,3 × 3,……199 × 199,200 × 200）,and then the best window area by the mean change point method was calculated. The result showed that Python module programming extracted the relief amplitude automatically and efficiently,mean change- point analysis method effectively detected the inflection point on the curve,and 2. 62km^2 was the best statistical unit area. Classes of relief amplitudes were gotten,and it was found that the relief amplitude between 30 m to 200 m has the highest proportion.