About precision and integrity in visual query languages for spatial databases

More and more users of different types have to deal with spatial databases and geographical information systems (GIS). The increasing number of "novice" (non-expert) users in the field of GIS and/or computing crucially require interfaces with a high degree of user friendliness. To meet this requirement, visual languages are seen as precursors. Nevertheless, current visual solutions suffer from different problems. Among them, imprecision and integrity problems are encountered in spatial relations. An extension of an existing model has been proposed which provides a precise topological expressive power for three objects in R/sup 2/. This paper details how this new model can contribute to solve the previous issues in the field of GIS and how it can be integrated into existing visual query languages.