Research On XML Based WebGIS And Model Realization

In recent years, with the rapidly development of the computer technologies, how to share spatial data and Interoperate through network becomes the primary research task of WebGIS.The main purpose of Web GIS is to realize the issue of spatial geographic Information and data sharing on the Internet, to make user be able to access GIS data straightway via web browser, and to execute such GIS functions as query, statistics, edit and creating thematic map of geographic data and business logic data. Theappearance of XML technologies bring Internet a new developing chance, which hasbeen paid more atention to by IT enterprises for its structuralization, extensibilityand flexibility, and its developing prospect is promising. As far as Web GIS isconcerned, XML can be used in standard storage for spatial data, data sharing,network transmission, electric map displaying and GIS software frameworkbuilding.This dissertation focuses on researching Interoperate in WebGIS Based on XML.Have discussed the rudimentary knowledges of GIS and WebGIS, inconcluding the definition, function, developing trend of GIS and the definition, System structure, realizing method, products introduction and facing problems of WebGIS It also introduces the basic knowledge of XML including the development character main application and related standards. Then it analgzes the problems when developing WebGIS.And it also puts forwards the developing ways of WebGIS accord with Open GIS rules. After analyzing and studying the interoperable conceptions and status quo of GIS, this paper puts forward the way to realizeinteroperability for WebGIS by technical means.OGC is an organization devoted to the standardization of Gis, it set down a series of specification about open spatial data interoperability. GML is an specification of spatial data express, is the application in the domain of Gis. It inherits all advantanges of XML and is ideal language expressing spatial data, and is one of keytechnologies to realize spatial data sharing. GML based on XML is the foundation of geospatial data expression. An application standard of XML WIDL technical makes it possible to interoperate among different WebGIS system. 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 sits out instances, to show the constructive process and technical method about graphics display on browser of WebGIS application. It makes the application system extensible and exoteric with middle Mobile Agent. At last, this paper makes a conclusion, and presents the next works on the model design.