"This interferogram used radar images from ESA’s ERS-2 and Envisat satellites to show an area of approximately 30 x 35 km around the city of Las Vegas in the US. The city is visible in the centre of the image as an area of bright colours, with the city’s major thoroughfares appearing as straight dark lines. The image was produced by the Oberpfaffenhofen Remote Sensing Technology Institute of the German Aerospace Centre (DLR) under an ESA project to study the uses of joint ERS and Envisat data. An interferogram is an image generated by analysing the differences between two...