© Crown copyright and database rights 2025 Ordnance Survey 0100031673

OS Terrain® 50 models landscape features and is designed to be interoperable with small-scale mapping products for analytical, modelling, planning and visual purposes. OS Terrain 50 is available as a grid of heighted points at 50 metre post spacing and contours with 10m intervals (including mean high water and mean low water boundaries and spot heights). It is aligned to British National Grid (EPSG:27700) with height relative to Ordnance Survey Newlyn Datum with an accuracy of 4m RMSE. The product is updated annually in July and maintained/synchronised with other OS product updates. It is supplied as bespoke area cut-outs or 10km x 10km tiles.