【作者】 郭超颖；

【导师】 毕华兴；

【作者基本信息】 北京林业大学 ， 地图学与地理信息系统， 2008， 硕士

【摘要】 数字高程模型(DEM)作为空间数据库的主要内容之一,已经被广泛应用于诸多领域;数字地形分析是在DEM上进行地形属性计算和特征提取的数字信息处理技术,研究基于DEM的数字地形分析可以为多个领域提供地形分析的基础理论及实现手段。DEM水平分辨率在地形信息容量及精度等方面存在显著差异,是确定地形参数和应用尺度的重要指标。辨析DEM数据的尺度效应,研究不同DEM水平分辨率对数字地形分析的影响具有十分重要的现实意义。本文以陇东黄土高原地区马莲河流域为研究对象,构建流域数字高程模型,基于不同DEM水平分辨率进行流域地形特征的提取与分析,探讨不同DEM水平分辨率对地形特征及流域水文特征的影响;从流域地形特征及水文特征出发,确定小流域分类关键因子,将马莲河流域按照不同的地形特征分割为若干类小流域,为马莲河流域提供基础性数字地形信息资料,为流域的综合管理提供参考。研究表明:(1)在同一比例尺下,随着DEM水平分辨率的降低,对实际地形的模拟精度逐渐降低,对坡度的损失度较大;对地形坡向的影响较小,对坡向的刻画程度趋于粗略;坡度及坡向变率各项统计参数随之逐渐降低;对地形特征的描述准确度降低,地面水平方向的弯曲逐渐被忽略,难以体现真实的地表弯曲状况。(2)随着DEM水平分辨率的降低,提取的流域河流条数减少,河流总长度降低;马莲河流域最小沟谷集水区域面积逐渐增大,流域破碎度降低;相同阈值下,流域总面积不断减小,流域分割个数随之减少;在较高的DEM水平分辨率下,可以提取出更加复杂的水系形态,体现更加细小的河流网络,得到更为碎散的流域分割结果。(3)选取在小流域产汇流过程中影响较大的流域面积、流域圆度比及小流域沟壑密度作为主要分类因子,采用分层分类法,建立树状结构分类标准框架,将马莲河流域52个小流域按照地形特征依次划分至八种流域类型,为马莲河流域的综合管理提供基础依据。更多还原

【Abstract】 Digital Evolution Model (DEM) is one of the most important part in the spatial database, the DEM has been adopted in many scopes digital topography analysis is a kind of digital technology to analyse the property of topography and distill the characteristics, which is based on DEM image. This kind of technology can provide more basic theories and practices to analyze the topography in wide scopes. The resolution of the DEM image could result some great differences for the capacity of geo-information and precision of the Geo-information etc.This study is focusing on Malian River watershed which is located on LongDong Loss Plateau; a DEM of the watershed will be constructed. To distilling and analyzing topography characteristics by using different horizontal resolution of the DEM image would provide basic digital topography information to do researches on the influences of the topography and hydraulic characteristics with different horizontal resolutions of the DEM image in Malian River watershed.a) With the same scale, the topography can be ignored along with the low horizontal resolution of the DEM image and the modeling precision for the topography is getting lower as well, so that it influences the slope gradient negatively. However, it does not influence the direction of the slope too much, the quality of slope direction image is getting lower; the variability parameters of slope gradient and slope direction are getting lower; the precision topography characteristics is reduced, and the ground curvature ration can be ignored gradually, so that it is hard to reflect a realistic ground curvature situation.b) Along with the reduction of DEM image horizontal resolutions, the amount of rivers are decreased in the watershed, the total distance of the river is getting shorter; the catchment area of the smallest valley is getting larger, the fragmentation of the watershed is getting lower; with the same threshold value, the watershed area becomes smaller continuously, the amount of fragmentations of the watershed are reduced; the much more complicated hydraulic system, more detailed stream grid and more fragmented catchment can be resulted with high resolution of the DEM image.c) The watershed area, watershed roundness ratio and the valleys intensity in SSC watershed are selected as major classification factors. The tiered classification method is used to construct a standard framework for tree classification. 52 sub-catchments will be classified as 8 types of watershed in accordance with the topography characteristics in the Malianhe watershed.更多还原