One of the most crucial tasks by methods of earth observation is to identify the distribution of people in impassable or insecure areas, or in emergencies of unclear situation. In the humanitarian sector, this applies mostly in the detection of urban growth, the discrimination of districts, and the classification and counting of building types. Optical data outperforms most of the SAR sensors regarding their spatial resolution. But still, SAR imagery can be used to identify dwelling densities or temporal changes. The figure below shows a colour composite of three TerraSAR-X scenes for a small part of the Minawao refugee camp, Cameroon. It shows that some parts of the camp remain stable during this period (white) while others were removed (red and yellow), displaced or newly built (blue) before the last image was acquired.
