Fraunhofer Institute IAIS - Intelligent Analysis and Information Systems, Schloss Birlinghoven, Sankt-Augustin 53754, Germany;Fraunhofer Institute IAIS - Intelligent Analysis and Information Systems, Schloss Birlinghoven, Sankt-Augustin 53754, Germany;240 giCentre, City University, London EC1V0HB, UK;Department of Geoinformation Processing, Faculty of Geoinformation Science and Earth Observation, University of Twente, 7500 AE Enschede, the Netherlands;Department of Computer Science, University of Rostock, Rostock D-18059, Germany