Al Kufrah oasis, satellite radar image. North is at top. This oasis is in the desert of south-eastern Libya. The colours indicate different reflectivity of the radar. Artificial structures and bare rock (yellow) stand out from the sandy background (purple). Aquifers (hexagonal and circular, lower right) supply water for the settlement (buildings at top right) and the palm tree plantation (top centre). This image, showing an area around 14 kilometres across, was obtained by the TerraSAR-X satellite on 2 February 2009. This is a European satellite that uses X-band (microwave) synthetic aperture radar (SAR) to observe the Earth from space.