1. An apparatus for generating cross-modality semantic classifiers, the apparatus comprising: a memory; and at least one processor device, coupled to the memory, operative to: (a) use Geographic Information Service (GIS) data to label satellite images; (b) use the satellite images labeled with the GIS data as training data to generate semantic classifiers for a satellite modality; (c) use the GIS data to label Global Positioning System (GPS) tagged ground level photos; and (d) use the GPS tagged ground level photos labeled with the GIS data as training data to generate semantic classifiers for a ground level photo modality, wherein the semantic classifiers for the satellite modality and the ground level photo modality are the cross-modality semantic classifiers.