重采样方法对DEM地形表达的影响分析

The analysis of slope flatting caused by DEM resampling

重采样方法是获取不同分辨率DEM数据的主要手段之一,同时也影响DEM地形表达的能力。本文采用坡度和剖面曲率作为分析重采样影响DEM地形表达的因子,通过比较利用重采样方法生成的不同分辨率DEM的坡度和剖面曲率,分析重采样方法对DEM地形表达的影响。以5m分辨率DEM为基础重采样为10m、20m、40m水平分辨率DEM的实验表明,重采样过程中随着DEM分辨率的降低,坡度整体呈减小趋势,地形趋于平缓,坡度高频部分损失严重;剖面曲率随着重采样后DEM分辨率的降低,其频率分布曲线由分散变得集中,表明地形信息丰富的高分辨率DEM由于重采样方法而造成地形信息丢失,空间结构简单化。

： Based on 5m resolution DEM obtained by 1：10000 digital topographic maps, the slopes of 10m, 20m, 40m resolution DEM are obtained by resampling. Frequency analysis of slopes shows that the DEM slopes decrease as its resolution became lower, i.e. , smaller slopes frequency increased, larger slopes frequency decreased. The real experiment results show when DEM resolution is higher, the difference concentrated in the smaller slopes. The difference distribution of curvatures became more dispersed and concentrated in the larger slopes while the DEM resolution is lower. After study of the profile curvature frequency, the curvature of profile become smaller for lower resolution resampling, which indicates lose of topographic information and simplification of spatial structure of DEM.