Research On The Method And Application Of Vector Spatial Data Transition Based On GML

The appearance and development of Web GIS has broken the closed system of traditional GIS data, but it provided an open platform for the spatial data sharing and communion. The spatial sharing also faced many problems to resolve, such as territory distribution, all kinds of obtainable means, and various storage formats. Those are all complex characteristic that may not easy to deal with. In order to realize the spatial data sharing and interoperation better, it became a current focus on researching the transition of spatial data.The development of Web brings about GML.GML is important for the GIS application .OGC(Open Geospatial Consortium)has set down the Geography Markup Language based on XML (Extensible Markup Language).It is a special specification for spatial data sharing and exchanging on the Web.GML can describe varied complex data and separate the data content from the data format, so it is possible to depict different data source by the uniform spatial data model.The text encircled the masterstroke of the vector spatial data transition based on GML.The author analyzed particularly the diversity of many geographic data sources and expatiated on the demand of geographic data integration on the net. The paper also studied the several traditional spatial data transition format. After summarizing the shortage of these traditional methods, combining the technical and theoretic elements on vector spatial data transition, the author researched the method based on GML.GML worked as the middle standard in spatial data transition, depicting geographic spatial feature using a uniform spatial data model.With the theoretical research, the paper actualized a method of vector spatial data conversion based on GML.Thus can resolve the interrelated matter of spatial data sharing further. The keystone of the method is as follows. Firstly, the author realized the function on the server end, read the vector spatial data source from Internet and local space using Java language, and created GML file according to the simple feature geography model sustained by OGC.Each geographic feature can express as 'FeaturecCollection', which is composed of geometry data and attribute data. Secondly, the author realized the function on the client end, parsed the GML data byDOM technique. As long as we knew the exterior transition format of spatial data, we could create corresponding vector spatial data based on GML, which is a middle tache. Thirdly, for the sake of issuance of transition application, the author made use of the technical of C/S. Therefore, it made possible to run the application at the same time by several GIS platform, and realize spatial data sharing better.After the experiment, we can make a conclusion that the spatial data transition based on GML is an effective method and has a bright future.