基于不同分辨率DEM的永寿县地形信息差异分析

Analysis of Topographic Differences of Yongshou County Based on Different Resolutions of DEM

高分辨率的DEM往往可以囊括更多更详细的地形信息,但过于详细的数据可能会造成数据冗余给计算带来不便。为了研究不同分辨率的数字高程模型(DEM)在对地形信息表达的现实意义,基于不同比例尺、不同栅格空间分辨率的DEM进行了地形特征的提取与分析,结果表明:(1)地面整体坡度随着分辨率降低逐渐减小,对地形的描述越来越粗糙,概括性越来越高,地形整体趋于平坦化。(2)基于较小分辨率DEM提取的坡向更具有宏观意义,而高分辨率DEM提取的坡向可反映地形的细部朝向。(3)随着DEM分辨率下降,地面平面曲率能更加概括区域地形,使山谷线和山脊线更明显,但会导致大量细部信息的丢失。(4)DEM所提取的地面剖面曲率值随着DEM分辨率的下降显著减小,即地面坡度的变化减小,地面的转折棱角逐渐趋于平滑,地形起伏变化特征精度降低。

High-resolution DEM can include more detailed topographical information,but the excessively detailed data could make it redundant and even cause data to be inconveniently calculated.In order to research whether different levels of resolution of the DEM(digital elevation models)has a very important practical significance on the terrain information expression,based on different scales and different resolutions of DEM,we extracted and analyzed topographical feature.The results showed that:(1)with the gradual reduction of resolution of DEM,the overall slope of the ground was decreasing,the description of the terrain was getting rough,and the topography became more and more coincident,the terrain tended to be more flattened;(2)the slope extracted from low resolution of DEM had better macro meaning,while the slope extracted from high resolution of DEM could reflect the fine orientation of the terrain;(3)with the reduction of the resolution of DEM,surface curvature could generalize regional topography better,and the mountain ridge line and valley line would be more obvious,but this would lead to loss of a lot of detail information;(4)with the decrease of the DEM resolution,the profile curvature information extracted from DEM would be dropped significantly,in other words,the decrease of the DEM resolution made the variety of terrain slope less,the turning point of the ground tend to be smooth gradually,and the characteristic of the topographic fluctuation reduce.