【作者】 韩富江；

【导师】 刘学军；

【作者基本信息】 南京师范大学 ， 地图学与地理信息系统， 2007， 硕士

【摘要】 数字地形分析是以数字高程模型(DEM)为基础数据进行地形属性计算和特征提取的数字地形信息处理技术，是进行各种与地形因素相关的空间模拟的基础技术。可视性分析是数字地形分析的重要组成部分，也是GIS空间分析中不可或缺的内容。目前，可视性分析时均认为DEM栅格单元内部的地形是没有变化的(DEM格网尺寸比较小的情况下可以这样考虑)，是同质的，高程处处相等。但实际上DEM栅格单元内的地形是千变万化的，存在着一定的变异性，即DEM栅格单元地形异质性，DEM栅格单元地形异质性的存在可能得出与实际不符的可视性分析结果。因此，研究DEM栅格单元地形异质性对可视性分析的影响大小及影响规律，从而提高可视性分析的精度，是十分必要的。本文以DEM栅格单元地形异质性为切入点，利用对比分析、数理统计等方法，系统地研究了DEM栅格单元地形异质性对可视性分析的影响及影响规律。首先在总结前人对空间异质性和地形复杂度的研究成果基础上，明确了DEM栅格单元地形异质性的定义，并从定性角度分析了其形成原因，从定量角度提出了DEM栅格单元地形异质性的量度指标——DEM栅格单元地形异质性指数(DGTHI)；其次，通过对不同水平分辨率DEM上的栅格单元地形异质性指数的对比，分析讨论了DEM栅格单元地形异质性与DEM水平分辨率的关系；最后，对不考虑DEM栅格单元地形异质性和考虑DEM栅格单元地形异质两种条件下得到的目标最大可视百分比和最佳观察点位置进行了对比分析，研究了DEM栅格单元地形异质性对可视性分析的影响及影响规律。研究结果表明可视性分析对DEM栅格单元地形异质性比较敏感，在低分辨率的DEM上进行可视性分析时，应当充分考虑DEM栅格单元地形异质性的影响，以提高可视性分析结果的精度。更多还原

【Abstract】 Digital Terrain Analysis (DTA) is a topographical information analysis technology that calculates and extracts terrain surface parameters and morphological features on Digital Elevation Model (DEM). DTA forms a foundation for spatial simulation related to terrain surface. Visibility analysis is an important component of DTA and it is also the indispensable part in GIS spatial analysis. At present, when visibility analyses are performed, terrain surface inside DEM grid is thought to be a plane and homogeneous, elevation be equal everywhere. In fact, terrain surface inside DEM grid is uneven and has some variabilities, these variabilities are named DEM grid terrain heterogeneity. Results of visibility analyses do not possibly correspond with results from real-world terrain surface because of the existence of DEM grid terrain heterogeneity. Therefore, study on effects of DEM grid terrain heterogeneity on visibility analysis is very necessary.This paper takes DEM grid terrain heterogeneity as a breakthrough. It adopts Comparative Analysis and Statistical Analysis methods to systematically analyse effects of DEM grid terrain heterogeneity on visibility analysis. Firstly, the definition of DEM grid terrain heterogeneity is definitely defined on the basis of summary of the former research on spatial heterogeneity and terrain complexity. Meanwhile, its forming reasons are qualitatively analysed and a quantitive index (DEM Grid Terrain Heterogeneity Index, DGTHI) is put forward. Secondly, the relationship between DEM grid terrain heterogeneity and DEM horizontal resolution is analysed and discussed by the comparison of DEM Grid Terrain Heterogeneity Index on different horizontal resolution DEM. At last, the effects and fluencing rule of DEM grid terrain heterogeneity on visibility analysis are studied by the comparison of biggest percent target visible and best viewpoint site under conditions of taking no account of DEM grid terrain heterogeneity and taking account of DEM grid terrain heterogeneity. The result shows visibility analysis is more sensitive to DEM grid terrain heterogeneity. So DEM grid terrain heterogeneity should be considered when visibility analyses are performed on lower horizontal resolution DEM.更多还原