Research On Spatial Data Sharing Based On GML3.1

GIS (Geographical Information System) is an information system, which collects, stores,analyses, processes and displays the geographical information. The Internet and distributed computing technology provide the hardware for share and exchange of spatial data. With the development of ORDBMS technology, it enables the storage of huge scale of spatial data. The expansion of GIS needs the share and exchange spatial data. A geographic information system with open interface will promote the spatial data exchange and sharing s among different departments.It is important for the complexity and integration of geographical information system to open and standardized operation interface, which enables different system to interoperate in a standard way and ensure the validity and efficiency of operations. Many domestic and international organizations have set up standards of geographical information. The OGC (Open GIS Consortium) is international standardization organization with influence. The OGIS (Open Geodata Interoperability Specification) intends to implement sharing and interoperating spatial data by open geographical information system with industry standards and open interfaces. OGIS has mainly two specifications: abstract specification and implementation specification. As the newest version of GML ( Geography Markup Language) ,GML3.1 is involved in the dissertation, which is released by OGC in February,2004.In the dissertation , the modes of spatial data sharing are discussed theoretically, and the implementation approaches of applying GML3.1 to spatial dada sharing are researched.Beginning with the problems of recently using spatial data, the dissertation introduces the framework of OGIS, and fully summarize the Geo-spatial data encoding implementationspecification——GML3.1,which is constituted by OGC and is based on XML (extensibleMakeup Language) .Especially, it discusses deeply the models and framework of GML3.1. Based on the combination of GML3.1 and Chinese National Spatial Data Transfer Format (CNSDTF) ,Chinese Geography Markup Language (CGML) is put forward.The modes of spatial data sharing are completely researched, including the traditional modes of spatial data sharing, the interoperable method, Seamless Integration of Multi-source Spatial-data (SIMS), Web Service technique and the spatial data sharing based on GML3.1.Depending on the theoretical study as above, the author proposes the spatial data standardization based on GML3.1 and the WebGIS construction based on GML3.1, and discuss the metadata sharing based on GML3.1. Through the analysis of the exterior data exchange formats of Arc/Info and Maplnfo, the implementation algorithms for convert the two data formats into GML3.1 are given. At the same time, the WebGIS architecture based on GML3.1 is designed.