PROPOSAL OF 3D GIS FOR SPATIAL DATA VISUALIZATION AND ANALYSIS OVER INTERNET

Nowadays, sharing and querying spatial data through Internet has been become ubiquitous and easier in term of visualization and analysis. Thus, GIS (Geographic Information System) is no more an isolated application used by a limited number of users, but essentially a worldwide shared set of complex geo-applications. Any more, many concepts combining both GIS and Internet have been occurred, i.e. WebGIS, Internet-Based GIS, GIS Web mapping, etc. Nowadays, the application of the 3rd dimension in Internet-based GIS, with rare exceptions, is restricted and limited to research work. Thus, this paper proposes a contribution in 3D GIS deployment over Internet. After a discussion of the advantages and limits of current Internet-based GIS, this work highlights a proposal of a multilevel spatial database structure implemented in PostgreSQL/PostGIS. Then, the paper gives details about data integration in spatial database from different types of data sources. Finally, it proposes a set of functionalities to visualize and query 3D spatial data within Internet. Spatial data visualization and analysis is based on layer management. The layers are defined dynamically by users through spatial and semantic queries. Hence, the GIS is composed of a set of superposed layers. Each layer structure can be stored for further use and can be shared by different users. Java applets provide to each distant client connected to the spatial databases the possibility to design his own set of layers, visualize and analyze 3D geometric and semantic data in an Internet viewer.