Kalahari Desert, Namibia, satellite image. This is the edge of the Kalahari Desert where sand dunes (yellow lines) are encroaching on mostly abandoned farmland. The Nossob River (black, white shores) runs from top to bottom. The merging point of the Black and White Nossob rivers is at upper centre. A road (white) runs alongside the river's right- hand bank. The image is about 50 kilometres wide. Image acquired in visible and infrared wavelengths on 14 August 2000 by the Landsat 7 satellite.