Grand Canyon, LiDAR satellite image. Located in Arizona, USA, the 6-million-year-old Grand Canyon system is a set of gorges eroded from the rock by the Colorado River. It extends for hundreds of kilometres, is nearly 30 kilometres wide, and at its deepest is 1.5 kilometres deep. LiDAR combines optical and laser imaging to produce digital elevation maps (DEMs), with differences in elevation shown by the colour-coding of the image. Image data obtained by the radar and optical sensors on the Advanced Land Observation Satellite (ALOS) of the Japan Aerospace Exploration Agency (JAXA).