Study On The Method For Plug-in WEB 3DGIS Spatial Data Storage And Topological Relations Query

GIS originated in cartography.And it described the geographical phenomenon using two dimensional data in the later.With the development of the cognition of realistic three-dimensional world and the urgent requirements of geological,mine,hydrological and other fields,3D GIS gradually attract people's attention.And it includes pseudo-3D represented by 2.5 dimensional and real 3D.The function of the former mainly stopped at 3D visualization stage.The latter is the base of 3D spatial query and analysis operations.So finding a complete and efficient spatial 3D data model to express real 3D phenomenon has been focus and hotspot in the research of the GIS industry.As the most basic and most important spatial relations,the study of topological relations and 3D topology data structure is the priority among priorities.On the other hand,real 3D spatial query and analysis systems in some specific areas can only be run independently in the locality and unable to realize distributed data sharing and interoperability based on the network platform.With a view to two aspects above,this paper using topological relations among five elements which includes Complex-obiect,Body,Surface,ARC and Node to establish spatial database and realize build 3D geological body dynamically and query it's 3D topological relationship in the real 3D and distributed data sharing and interoperability aspects.On the basis of distributed virtual reality,do a lot of research of 3D spatial data model and the method of modeling.Besides,build 3D geologic body of topological reconstruction with three steps.1.3D topological elements were stored and organized in relational data base,including Node ARC,Surface and Body.2.Using JavaScript language and EAI interface,transmitting topological data to VRML scene.3.Making use of PointSet node,IndexedFaceSet node and IndexedLineSet node to draw 3D geologic body in VRML scene embedded in the HTML page.Finally,querying topological relations of 3D geological model with the help of ASP technology.This paper studied provide a complete train of thought about building complex 3D object dynamically under the network environment and have a certain reference for realizing 3D GIS spatial analysis function which including 3D clipping,3D spatial query,arbitrary section building and so on.In addition,the conclusion laid a good foundation for spatial analysis in the future.