Since 2005 Eberhard Knobloch has served as president of the Académie Internationale d’Histoire des Sciences (Paris), and since 2002, as academy professor of history of science and technology at the Berlin-Brandenburg Academy of Sciences and Humanities and at the Technical University of Berlin (since 2009 em.). Being one of Topoi’s principal investigators, Eberhard Knobloch is project leader of the Alexander von Humboldt research group and of two series of the Leibniz edition. In his capacity as mathematician and classical philologist he is especially interested in the ancient mathematical sciences. Geodesy and land surveying were based on mathematical methods and instruments and deeply influenced by cosmological and astronomical considerations. The writings of Hyginus Gromaticus are of highest importance in this respect.