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LIDAR Composite DTM 2017 - 50cm

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This dataset is no longer available on the Data Services Platform. New version of the LIDAR Composite DSM data is available here: https://environment.data.gov.uk/searchresults;query=lidar%20composite%202020;searchtype=All;page=1;pagesize=20;orderby=Relevancy The LIDAR Composite DTM (Digital Terrain Model) is a raster elevation model covering areas of England at 50cm spatial resolution. 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 possible coverage. Where repeat surveys have been undertaken the newest, resolution data is used. The composite is updated on an annual basis to include the latest surveys. The DTM (Digital Terrain Model) is produced from the last return LIDAR signal. 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. Available to download as ASCII files in 2km grids, data is presented in metres, referenced to Ordinance Survey Newlyn, using the OSTN’15 transformation. All LIDAR data has a vertical accuracy of +/-15cm RMSE. 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. You can also download survey index files which shows, for any location, what Time Stamped survey went into the production of the LIDAR composite. 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 500,000 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 Environment Agency’s open data LIDAR archives includes the Point Cloud data, and derived raster surface models of survey specific areas and composites of the data available in any.