Light Detection and Ranging (LIDAR) is an airborne mapping technique, which uses a laser to measure the distance between the aircraft and the ground. Up to 100,000 measurements per second are made of the ground, allowing highly detailed terrain models to be generated at spatial resolutions of between 25cm and 2 metres. The Natural Resources Wales composite dataset contains digital elevation data derived from surveys carried out over several years and covers approximately 70% of Wales. We are making available 25cm, 50cm, 1m and 2m datasets, supplied as terrain models (a representation of the ground level) or surface models (a representation of object heights such as vehicles, buildings and vegetation). In addition to the height information, geo-referenced, coloured, shaded relief imag
es at the same resolution as the input LiDAR data grids are available.