基于GML3.0的GIS拓扑数据建模与表达

GML是基于XML为互联网上地理信息的建模、传输和存贮而设计的编码标准。GML3．0是GML最新的版本，在GML2基础上作了很多扩展，对拓扑信息的支持就属于它新增的部分。章从需求、来源和发展等多个角度阐明了用GML为地理信息数据建模的必要性，可行性及其优势。介绍了GML3．0新增加的内容，功能和GML3．0里基本数据对象的层次关系。着重分析、研究了GML3．0中基本的拓扑数据类型，语义模型，句法规则以及拓扑数据建模方法，并基于它们给出了几个拓扑例图的GML3．0具体编码。

The Modeling and Expression of Topologic Data for GIS Based on GML3.0

GML is a coding standard for web application, which is designed for modeling, transfer, and storage of geographic information. Written in XML Schema, GML3.0 is the newest version of GML released at the beginning of 2003. Based on GML2, it has a great extension. The new parts include the support to express topological information. Through analyzing requirement and development of webGIS, this paper illuminates the necessity, feasibility and advantage of modeling geographic information by GML. It introduces the new parts of GML3.0 and the hierarchy of GML objects. More important, this paper studies topologic data type,the GML semantic models, syntactic rules and the modeling method of topologic data in GML3.0. Based on these techniques, this paper also presents GML codes of some topologic graphs as concrete examples.