The vision of mapping the global urban footprint using the TerraSAR-X and TanDEM-X mission.

How much of the Earth’s landmass is urban, and where are these urbanized areas located? Be-cause of the key role of cities in sustaining human civilization and their impact on the environ-ment, there is a substantial need for and interest in global mapping of human settlements. Satel-lite sensors provide one of the few globally existing spatial data sources of observations. The German space mission TanDEM-X will acquire two coverages of the entire landmass for 2011 and 2012. This study presents a developed pixel-based classification approach aiming to extract urban and non-urban structures from single radar imagery. The intended product, the so called ‘urban footprint’ is presented for selected cities, thematically defined and accuracy assessment is carried out. Beyond that sample applications are discussed and one example, the mapping and monitoring of urban growth is applied