Based On Webgis Based On Xml And Its Data Sharing

With the rapid development of the computer , network and spatial technology. The traditional GIS is developing to webgis. Webgis now is becoming the popular information implement. Thousands of web sites provide the service of the geospatial information. Although we have to encounter the fact that all those geospatial information can not work together, also it is hard to using our web browser to seamlessly read and access them. For business policy and data security, most of these data resources consist in legacy systems and isolated in desktop applications, it is hard to provide enough supports for spatial decision-making and sharing.Furthermore from the geospatial information accessing to digital earth, the sharing of geospatial information is the core problem. So the geospatial information sharing is the most important technology of the construct of the digital earth.This dissertation focuses on researching the new network technology and it's applying in the GIS. Firstly it introduces the OpenGIS and the characteristic of the GIS, analysises the state of webgis, discusses the the implement technology of WebGIS. In the base of those theories, then discusses to the core content :the research on WebGIS and it's data sharing based XML.Geospatial-data is the basic data source of webgis, which has several characteristic: multi-sources, multi-semantics, multi- space-times, multi- scales and complex get-ways. Although HTML now is the universal sign language for web, Simpleness is it's advantage, also it's shortcoming. Thus HTML is disadvantage to describe the structural geospatial data and the implement of geospatial-data sharing. So we need the web language to effectively describe the geospatial data,and XML is the result. XML is to be the new web language,and it's the perfect medium to sharing and altering the geospatial-data. Researching and developing the object-orient sign language, especially the geospatial-object orient sign language is the available approach to implement the sharing and altering of geospatial-data. GML is put forward for this purpose. GML is a strongly implement to encoding the geospatial-data. It bases the XML, and provides the feasible approach to the data spacing and altering in webgis.The main content of the research is to use XML/GML technology to build webgis, discuss the theoretics of data sharing in webgis based XML, implement the geospatial information sharing and integrating based XML. The content include:(1), Put forward a valid way to store and use the distributed geospatial-data. (2), Researching the technique of the maping and conversing between the XML data and non- XML data. (3), Using GML as the describe language and developing the GML's data-modeling and database storing technology. (4), Researching the query and visualized technology of XML data in webgis.XML/GML-based webgis now is a new field, the research and development on it will not only bring forth great impact on traditional conception and traditional technology, but also greatly affect the industries of webgis. Using the XML in webgis is now in the developing, this dissertation do the elementary research, if there are deficiencies in this dissertation, please point them out. Thanks!...