Summary

An information system is a question‐response system based on a data set. Such systems contain tools for the computational analysis of information. If the stored data have a spatial reference, the system is called geographic information system (GIS). It allows the interrogation and display of attribute values based on spatial criteria and vice versa. Hence the term data analysis, that includes all those analysis, queries, evaluations etc. that can be performed on structured and stored geodata. Queries can be performed according to different approaches: thematic, geometric and topological. Geometry is expressed by the spatial reference, which is assigned to all objects. They fulfill the requirement of location and extension. The topological properties are expressed by the relations of neighborhood, containment, and overlapping etc. Besides geometric characteristics that exist for spatial data, there are also thematic properties. Those properties are stored in tables. A query can be classified in two ways, depending on the result. In a direct query, there is a subset extracted from the database and the original data are not modified by this process. In a manipulation, new space related information elements are generated, which can be used in further analysis operations. The results of data processing and data manipulation in GIS should be represented in a form which is understandable for the user, or in a form which enables data sharing.