OS Terrain 50 technical specification

The purpose of this technical specification is to:

  • Provide users with a brief description of the presentation of OS Terrain 50 in its supply formats.

  • Provide licensed system suppliers with as much detail as necessary to enable OS Terrain 50 files to be easily understood and processed by application software.

Product overview

OS Terrain is the name given to Ordnance Survey’s height products. The two products available, OS Terrain 5 and OS Terrain 50, provide detailed three-dimensional digital terrain models (DTMs) of Great Britain. A DTM primarily defines the ground surface, having removed all protruding features (such as buildings and trees) elevated above the bare earth. The main difference between the two products is their level of resolution:

  • OS Terrain 5 is a mid-resolution DTM, designed to be interoperable with our large-scale data.

  • OS Terrain 50 is a lower-resolution DTM product, designed for landscape visualisation and analysis over large areas. It is an Open Data product and, as such, it is free to view, download and use for commercial, educational and personal purposes.

Available formats

OS Terrain 50 is published as both grid data and contour data in a variety of formats. Both data types are created from the same source data and are supplied as 10km-by-10km tiles. These tiles are identified by quoting the National Grid reference of the south-west corner of the area they cover.

  • OS Terrain 50 grid: A grid of heighted points with regular 50m post spacing.

  • OS Terrain 50 contours: A contour dataset of 10m interval standard contour polylines. This includes mean high water and mean low water boundaries and spot heights.

OS Terrain 50 is available to download in the following formats:

  • A 50m grid in ASCII (American Standard Code for Information Interchange) grid and Geography Markup Language (GML) 3.2.1 (simple features profile – level 0)

  • 10m contours in GML 3.2.1 (simple features profile – level 0)

  • 10m contours in Esri shapefile

  • 10m contours in GeoPackage

  • 10m contours in vector tiles (MBTiles)

The product will be supplied separately for grid or contour as compressed folders for each geographic tile of data. Each compressed folder will contain data plus several additional files.

Index

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