GIS线目标间空间关系的集成表达方法

An Integrated Approach to Representing Line-line Spatial Relations in GIS

GIS中的线目标可以表达现实中一类广泛存在的空间实体,如地铁线、管线、道路以及河流等。以线目标为研究对象,基于分解与组合的思想,提出一种线/线目标空间关系的集成表达方法。在整体上,将空间关系分解为拓扑、方向和距离关系3种,并以拓扑关系描述作为方向和距离信息的载体,通过纳入局部的方向关系和距离关系,来集成表达两个线目标间的各种类型空间关系信息。其中在线目标间拓扑关系、方向关系和距离关系描述时,分别将它们分解为一组局部关系(或基本关系),并通过对拓扑关系建立一定的排列顺序来进行描述。最后,通过一个简单例子说明本文提出的方法与Clementini和Di Felice(1998)的不同,以及本文方法对表达各种空间关系信息的可行性。

Spatial relations play an important role in spatial query, analysis and reasoning. However, how to represent various kinds of spatial relations in a unified form is still an open issue. In this paper, an integrated approach is presented for representing line-line spatial relations. In this approach, spatial relations are decomposed into three types, including topological, directional and distance, and topological relation acts as a most basic information chain to carry directional and distance constraints for an integrated representation. At the same time, these three relations are also described based upon the idea of decomposition and combination. At first, a non-disjoint line-llne topological relation is decomposed into a set of basic topological relation units, and then these basic relation units are combined by the order of occurrence. In this way, local direction relation and distance relation are defined between two neighboring topological relation units, or between a relation unit and the corresponding endpoints of two lines, where local direction relation is described in a relative terms as left and right, and local distance relation is described by a partially Hausdorff distance. Furthermore, the ordered sets of local direction and local distance relations are constructed and obtained, respectively. Indeed, the integrated approach is very sound to represent the three kinds of spatial relations validly. A simple example is given to illustrate the advantage of the proposed approach in the paper compared to the existing ones.