VirGIS: mediation for geographical information systems

Geographic data have been collected for centuries and are available in a wide variety of formats and supports. VirGIS provides an integrated view of the data, and a geographical query language to access and manipulate integrated geographical data. Typical mediation approaches are data-driven and do not address the problem of integration of query capabilities. Geographic languages provided by GIS usually express spatial selections, metric or topological queries, allocations, etc., in addition to standard data manipulation. the VirGIS mediation system aims to integrate geographical query capabilities with GQuery, a XML geographical query language, and recent specifications published by the Open GIS Consortium (OGC) and adopted by major GIS vendors.