【作者】 杜微；

【导师】 陈学工；

【作者基本信息】 中南大学 ， 软件工程， 2010， 硕士

【摘要】 随着地理信息系统(GIS)的发展,数字高程模型(DEM)成为空间信息系统的一个重要组成部分,并且是工程建设、战场环境仿真等许多领域最为重要的基础数据之一。由于规则格网模型具有计算处理方法简单有效,且和遥感数据在结构上容易匹配等优点,其被视为DEM中最基本和最重要的一种模型。等值线图是在石油勘探开发、采矿、地质、地球物理、地球化学和气象等工程和技术领域内应用极广的一种图形,是众多领域成果表示的重要图件之一,它是一种形和数的统一。本文主要研究了以下方面的内容：基于格网的等值线生成和填充算法。在基于格网的等值线生成算法中,本文通过采用类似在平衡二叉树中插入结点的方法来选取和建立区间树的结点,通过扫描一次全部的格网单元就能建立起区间树的各级结点。在搜索给定的高程值时,仅对搜索路径经过的结点中的网格单元排序,避免了大量无效的排序,从而减少了搜索时间。本文提出了一种能够处理复杂多边形下等值线填充的算法。在确定各级等值线之间的空间位置关系时,本文利用格网中等值线与格网单元的关系,利用格网单元边界建立射线,采用射线法原理,能一次判断多个等值线间的包含关系,大大提高了算法的效率。更多还原

【Abstract】 With the development of Geographic Information System (GIS), Digital Elevation Model (DEM) has become an important part of spatial information system, and one of the best important and basic data in these fields, such as constructing project and emulating battlefield environment.The isoline graph has been widely used in engineering and technique field, such as oil exploration development, mining, geology, physical geography, geochemistry and meteorology, and it is one of the important maps that the achievement of many fields show. It also unifies shape and data.The thesis mainly researches the following contents:algorithms of isoline generation and fill based on grid model.In the algorithm of isoline generation, the process of selecting and creating interval tree nodes is similar with the process of insert nodes in AVL tree, Interval tree’s structure can be created by scaning all grids once.When searching the given altitude, we just sort those grids which are belonged to the nodes the search path passed, avoid sort all grids in the interval tree, reducing the search time。This thesis proposes an algorithm which can fill the isolines graph with random boundaries。When creating the location relationship between all isolines, this thesis utilizes the relationship between boundary of grid and isoline, use boundary of grid and isoline to create radials.By the theory of radial, we can get the location relationship between some isolines once time, and the algorithm is faster than the other algorithms.更多还原