空间拓扑查询

【作者】 张驰伟；

【导师】 陈学工；

【作者基本信息】 中南大学 ， 计算机应用技术， 2007， 硕士

【摘要】 在地理信息系统(GIS)中，作为空间关系的重要组成部分，空间拓扑关系一方面是地理信息系统数据库建立、空间特征存储、提取、查询、更新等操作的保障，另一方面它又为空间分析、辅助决策等提供了基础。因此，空间拓扑关系的研究已成为GIS研究的重点和热点。随着GIS应用的普及，空间数据库被广泛应用于各个部门。空间拓扑查询作为空间数据库应用系统的一个基本功能日益受到重视，并成为空间数据管理系统的空间数据管理能力的重要评判标准。本文主要对9交集模型的改进和拓扑查询应用程序的设计进行研究和探讨。9交集模型是目前发展最成熟和使用最广泛的拓扑关系模型，由于它对拓扑关系的描述是定性的，因此这种描述只是对现实世界中实体间关系的一种粗略分类。本文通过引入度量参数，利用拓扑和度量相结合的方法描述空间拓扑关系，细化了9交集模型对拓扑关系的分类，并设计了支持度量参数的拓扑查询应用程序。空间拓扑查询分为两类：(1)查找所有与给定对象满足特定拓扑关系的对象，即判断两个空间对象是否满足特定的拓扑关系；(2)查询两个对象间的拓扑关系。在第二类拓扑查询中，现有的决策树生成算法假定所有拓扑关系拥有相同的出现率，这种情况在实际中是非常少见的。本文通过设定拓扑关系的出现率，对现有的决策树生成算法进行了改进。基于改进算法生成的决策树比基于现有算法生成的决策树拥有更小的带权路径长度，更接近最优决策树。更多还原

【Abstract】 In geographical information system(GIS), as an important part of spatial relation, topological relation is the base for constructing of GIS database, storing and querying of spatial character, and topological relation provides the base for spatial analysis too. Hence, the study of the spatial relationship has important academic and practical scene in advancing the development of GIS. With popularization of the GIS application, spatial database has been widely used in various departments. As a basic function of spatial database application system, spatial topological query receives increasing attention and becomes the standard of spatial data management capabilities in spatial data management system. This paper mostly studies and discusses refining upon 9-intersaction model and designing topological query application.9-intersaction model is the most mature developed and most widespread topological relation model, it describes topological relations qualitatively, therefore the description is a rude classification of relations between entities in real world. This paper introduces the metric parameters, refines the categories of topological relations identified by 9-intersaction model via using the method with the combinations of topology and metric to describe topological relations, and designs topological query application with support to metric parameters.Spatial topological query is divided into two categories :(1)Find the objects that satisfy particular topological relation with given object, namely determine whether two objects satisfy particular topological relation. (2)Queries on the topological relation between two objects. Existing decision tree building algorithm assumes that all topological relations occur with equal probability, but this situation is extremely rare in practice. This paper refines the existing algorithm via assuming occurrence frequency of topological relation. Comparing with the decision tree built by the existing algorithm, the decision tree built by the refined algorithm has a lower weighted path length(WPL), and more closer to optimal decision tree.更多还原