矢量数据综合规则表达与实现方法——以土地利用数据综合为例

Research On Expression and Realization of Rules of Vector Data Generalization:A Case Study of Landuse Data

一库多用是GIS处理海量数据的有效方式。一库多用要求GIS能够从大比例尺数据生成小比例尺数据,这就要求GIS具备数据自动综合功能。GIS数据综合的关键是建立规则库,实现不同用户对规则库的自定义,以提高系统GIS数据自动综合的的通用性。GIS数据自动综合是计算机遵循的一定规则,对各个记录进行一一处理的过程。本研究基于产生式知识规则表达方式,提出"预存储规则"的实现方法。首先,最大量地收集与某一专题相关的所有知识规则,建立专题规则库;然后,根据相应的需求,在该专题规则库的基础上,通过用户接口定义不同应用规则库。该方法在一定程度上实现了程序与规则的分离和规则库的自定义。最后,给出了原型实验系统。

GIS is now used in more and more fields, h is required that GIS should be equipped more function. Peo- ple desire that the geo-data visualization should be with multi-angle, multi-point and multi-level. So GIS must be e- quipped with automatic data-generalization function. GIS relies on a rule database to realize automatic data general- ization. In this paper we suggest that automatic data generalization is a process using a computer to process every database record according to the rules. Based on the production-rule method, this paper proposed a method named Rules Pre-stored to enable users to define application rule database. According to the method, a GIS application first builds a thematic rules database which includes all the rules with respect to a specific theme. The rules data- base is called the theme rules database. Different users of the theme could define their own special application rule database based on the theme rules database through the user interfaces. A demonstration was also given. To some extent, the self-defined rule database and the separation of code and rules were accomplished. The result shows that the research idea and technical route are feasible.