基于XML的万维网地理信息系统的研究

【作者】 金世双；

【导师】 程景云；

【作者基本信息】 上海海事大学 ， 计算机应用技术， 2003， 硕士

【摘要】 随着WebGIS广泛的应用，不可避免地出现地理信息孤岛，特别是在实施数字地球战略计划中，这一问题越来越突出。因此，实现异构地理信息系统之间的数据共享、分布、互操作以及标准化的任务成为新的挑战，它需要寻求新的技术来解决WebGIS开放性的思路，克服传统互联网上固有的障碍。XML技术被称为是互联网领域的一次革新，它将创造性地发展WebGIS。 论文是在作者近两年来的理论学习和实践应用的基础上形成的，其主要内容有以下几个方面： 首先讨论了XML的基础知识，包括Web语言的发展，XML的特点和主要应用。其次在对WebGIS体系特点、发展现状进行深入分析的基础上，剖析了目前WebGIS开发面临的网上数据发布、数据互操作、数据挖掘和数据管理等方面的问题，提出了地理信息孤岛数据模型，以及指出WebGIS要想有长足的发展则必须走开放的道路，符合Open GIS规程。 论文对基于XML的WebGIS进行了深入地研究。伴随XML发展起来的地理空间模型标记语言GML，为空间数据表达奠定了基础。在此基础上，本研究实现了XML描述复杂的空间数据结构；实现了利用XML的应用标准资源描述框架(RDF)表达地理空间元数据；提出了利用基于XML的万维网接口定义语言(WIDL)技术，实现异构WebGIS系统之间互操作模型的构建；创造性地构建了基于GML的WebGIS应用系统的层体系结构模型，实现了WebGIS应用系统比较完善的建设方案，对客户端和服务器端的关键技术进行了深入的研究，通过实例展示了WebGIS应用系统中浏览器图形的显示，对服务器端应用层给出了使用移动代理模型，使得WebGIS应用系统具有扩展性、开放性。更多还原

【Abstract】 With the wider and wider application of GIS (Geographical Information System), isolated GIS islands come into being inevitably. These situations become worse in the process of implementing global strategic plan of Digital Earth. It is a new challenge for WebGIS to deal with geospatial data sharing, distribution, interoperation and standardization. It is perfectly essential for WebGIS to explore a kind of new technology, which can resolve the opening problem of WebGIS, and also can overcome the implicit limitation of Internet. XML is initialed a revolution in WWW field. It will remodel WebGIS in a creative way.After over two year’s theoretical research and practical application, I got such achievement as below:Discuss XML basic knowledge, including the development of Web language, characteristic and mostly application of XML. The technical characteristics of WebGIS and its developing status are analyzed in the dissertation. On the basis, it points out the new challenges WebGIS is facing of on data issuance on internet, data interoperation, data mining and data management and so on. It proposes a model of isolated GIS islands. It also indicates that WebGIS must track the opening way, measuring up Open GIS regulations.In the dissertation, WebGIS based on XML is deeply studied. It indicates that it is fully possible for XML to describe complicated geospatial data structure. Geospatial model language (GML) based on XML is the foundation of geospatial data expression; It proposes a novel idea about how to express geospatial metadata with RDF; an application standard of XML WIDL technical makes it possible to interoperate among different WebGIS systems. The dissertation constructs a system structure model of WebGIS application based on GML, It presents a rounded and constructive "layer" scheme of WebGIS application system, emphasize studied primary technology in the clients and Servers; It sets out instances, to show the constructive process and technical method about graphics display on browser of WebGIS application. It makes the application system extensibility and exoteric with middle Mobile Agent,更多还原