I thank the companies Laser-Scan, Oracle, ESRI and Bentley for their collaboration in this research and because I was able to use their software. In addition they gave me advice on technical issues. I appreciate the contribution of the NAM (Nederlandse Aardolie Maatschappij), the project-team of the HSL-Zuid and the Bouwdienst van Rijkswaterstaat because they provided me with 3D data on physical constructions for the case studies. AGI (Adviesdienst Geo-informatie en ICT) provided me with point heights of case study areas.Calin Arens, Friso Penninga and Erik van Nieuwburg contributed to several issues in this thesis (respectively the polyhedron implementation, the effective filtering of a TIN and the Internet application to query a database) as part of their MSc programme, Friso the last few months as a colleague.Finally there are a number of people who supported me in finishing this thesis in a more indirect way. To have these people around me give me the possibility to explore and experience the things in life that are essential to me. First of all I would like to thank Riet, Roel, Suzan and Marije (my family). They gave me the possibility in the first place to start my education and study and they always support me in doing what I find important to do. Secondly, I would like to thank all my inspiring friends who I either meet frequently or rarely. These contacts were very important to me during my research. There are two people who I like to mention specifically. Madeleine was essential for me during this period because of our spiritual discussions, her stimulation, and laughter. Finally, Gerbert, my soulmate, was of great importance to me because of his practical and mental support, his encouragement and understanding.