Topographical map of Africa, satellite radar data. This map uses elevation data from NASA's Shuttle Radar Topography Mission (SRTM) in February 2000. In 2004, this data was released for the first time for most of the African continent, shown here as a colour-shaded relief map. The SRTM data was obtained using C-Band Interferometric Radar and X-Band Radar. Colour-coding is directly related to topographic height, with brown and yellow at the lower elevations, rising through green, to white at the highest elevations. Blue areas on the map represent water.