On geographical on-line analytical processing (GOLAP)

Current geographical information systems (GIS) handle large amounts of geographical data that are usually stored in relational databases. GIS systems provide a possibility of spatial query evaluation on this data. As spatial queries are usually very expensive form the computational point of view, major database vendors developed special plug-ins in order to make retrieval of geographical data more efficient. For example, Oracle offers their Spatial Cartridge based on quad-tress, Informix offers the Spatial Data Blade based on R-trees, etc. This approach is suitable for those spatial queries, which select objects in certain user-defined area. It does not help so much in the case of analytical queries. On the other hand we can observe a fast development of so called OLAP systems, i.e. on-line analytical processing systems. The development of such systems has been originally motivated by the need to speed-up the process of analysis of huge amount of data stored in very large databases.