The ideas for this book were conceived during the last years when I was with GIs groups at the Technical University of Darmstadt (group of Hans Jorg Schek) and at Bonn University (group of din B. Cremers). The results in the book are closely connected with two research projects that have been supported by the German Research Foundation (DFG): the collaborative re search centre (SFB 350) "Interactions between and Modelling of Continental Geosystems" which was set up at Bonn University and the joint project "Interoperable Geoinformation Sys tems (IOGIS)". First and foremost, I am very grateful to Armin B. Cremers for the supervision of my habil itation thesis and the support of the GIs group. In the same way I am indebted to Agemar Siehl for his support during many years of collaborative work and for reading the manuscript from a geological view point at short notice. Without him I would not have arrived at Bonn at all. I thank Rainer Manthey for his valuable hints and Horst Neugebauer for his engagement within the SFB 350. He motivated me to write the English manuscript.