An 'oliebol' is a typical Dutch treat, traditionally eaten on New Year's Eve, and can be described roughly as a doughnut ball. The 'oliebollenbar' was a theme night at the Snelliusbar (the bar of the students association Snellius of the faculty of Geodesy, Delft University of Technology), organised by staff members of the GIS Technology group. Wiebke, Yahaya) and our guest researchers (Chen, João, Ludvig, Rod). I really enjoy working with this young, dynamic and enthusiastic group of researchers.Other OTB colleagues also contributed to the pleasant atmosphere in which I have worked for four years. Thanks to the 12 o'clock lunch crew, the 20 year OTB committee, the PhD council and board (I enjoyed both the work and the drinks) and all other colleagues that I met during joint projects, off-sites, OTBorrels and coffee breaks. Thanks to Itziar Lasa for the cover design of the dissertation version.A lot of people outside OTB also contributed in one way or the other. The week Peter and I spent at Oracle USA was invaluable (thanks to Siva Ravada, Ravi Kothuri, Baris Kazar, John Herring, Han Wammes), even though the annual 'A Quilters Gathering' created the most surreal atmosphere in the Nashua Sheraton. Discussing spatial data types during the day and being surrounded by hundreds of quilters with humongous trolleys with sewing kits and machines by night; it's quite a gap.