Light Detection and Ranging (LIDAR) is an airborne mapping technique, which uses a laser to measure the distance between the aircraft and the ground. You can also download survey index files which shows, for any location, what Time Stamped survey went into the production of the LIDAR composite. A tinted shaded relief, which is an image showing what LIDAR looks like when loaded into specialist software, is also available as a WMS feed. All LIDAR data has a vertical accuracy of +/-15cm RMSE. Available to download as ASCII files in 5km grids, data is presented in metres, referenced to Ordinance Survey Newlyn, using the OSTN’15 transformation. We remove surface objects from the Digital Surface Model (DSM), using bespoke algorithms and manual editing of the data, to produce a terrain model of just the surface. The DTM (Digital Terrain Model) is produced from the last return LIDAR signal. The composite is updated on an annual basis to include the latest surveys. Where repeat surveys have been undertaken the newest, best resolution data is used. Produced by the Environment Agency in 2017, this dataset is derived from a combination of our full time stamped archive, which has been merged and re-sampled to give the best possible coverage. The LIDAR Composite DTM (Digital Terrain Model) is a raster elevation model covering ~75% of England at 2m spatial resolution.
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