This friday Dipl. Geographer Christian Sengstock successfully defended his PhD thesis in the combined faculty for the natural sciences and mathematics of Heidelberg University. He developed a framework for Geographic Knowledge Discovery from User-Generated data. The thesis was supervised by Prof. Michael Gertz (co-PI at our CrowdAnalyser Graduate School) from the database research group at the Heidelberg University Department of Computer Science. As a member of the PhD committee Prof. Zipf congratulates Christian for his achievements and whishes all the best for the future!