Study On GML-Based WebGIS And Its Application

WebGIS combined Internet and GIS is a necessary trend of the development of the GIS software. But the difference in stored format, data model and data structure etc. results in the production of multiple sources data. How to integrate and publish the existing heterogeneous data including the GIS spatial data in various formats and how to use direct vector map in a browser to create highly interactive maps, all of the solutions to these questions depend on the new Web standard. The advent of XML gives an effective way. GML(Geographical Markup Language) is a XML application used for transmission and storage for geographical information.W3C (Word Wide Web Consortium) brings SVG(Scalable Vector Graphics) in order to fit the rapid development of Web application. SVG is suit of scalable vector graphics language description specification based on XML. Firstly, the paper analyses the primary implement method and formation model of WebGIS in detail, analyses the systematic framework of J2EE. A technologic project for GML-Based WebGIS application system under J2EE systematic framework is brought forward. Secondly, based on description of GML specification, the paper uses GML specification to defining and description GIS spatial element. The application Schema of GML document is given. An arithmetic for transferring spatial data stored in Oracle database into GML is designed. A storage method for GML in Oracle database is provided. Technologic support for GML-Based WebGIS application system is provided. Thirdly, considering static grid graphics can not satisfies the visualization of Internet map requirement, the paper designs an arithmetic for transferring GML into SVG and editing spatial data. It shows highly interactive vector map in browser directly. It implements the publishment and inter-operate of spatial data in vector map method SVG-based . Finally, the paper combines the thought of computer support co-work(CSCW). It uses task group management mechanism.It uses the method of edition-management to implement co-edit. A co-edit system for spatial data based on WebGIS is designed. It implements co-edit for spatial data.