# OS Terrain 50 Documentation

OS Terrain 50 is an open height dataset of contours with spot heights, breaklines, coastline, lakes, ridges and formlines for Great Britain. Both [OS Terrain 5 ](https://docs.os.uk/os-downloads/products/land-and-terrain-portfolio/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.

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**This product is updated annually in July.**
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<figure><img src="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2FPLfF3KccOOwclXGKsUwo%2Fimage.png?alt=media&#x26;token=05f38652-6715-42dd-b26c-19758ae74fd1" alt="A representation of OS Terrain 50 data showing contours in a mountainous area in Great Britain"><figcaption><p>A representation of OS Terrain 50 data</p></figcaption></figure>

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 southwest 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.

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**Model wind direction and lines of sight**

Make better decisions about where to locate wind turbines and mobile phone masts. OS Terrain 50 lets you model wind direction and lines of sight at an early stage of planning and development, meaning fewer site visits.

**Plan landscape defences**

Get the bigger picture about flood risk, soil erosion and pollution. By showing steep hillside gradients, OS Terrain 50 helps you plan flood defences and safeguard the landscape.

**More engaging maps**

With the contours version of OS Terrain 50, you can shade in hills to show their height. This extra sense of depth is ideal for walking maps and apps.

**Surface model entire landscapes**

Get an accurate, uncluttered view of the terrain with the grid version of OS Terrain 50. Its 50metre post spacing gives you a surface model of the entire landscape, including major roads, large lakes and estuaries.

**Take account of tides**

The contours dataset also includes mean high and low water boundaries.
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OS Terrain 50 can be used in conjunction with various OS digital products for analytical, modelling, planning and visual purposes, including:

* Asset / site management
* Signal propagation
* Environmental analysis
* High-level development
* Geological analysis
* Line of sight planning
* View shed modelling
* Using the product as a visual aid
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{% tab title="Summary" %}

* **Access:** Download via the [OS Data Hub](https://osdatahub.os.uk/)
* **Data theme:** Height
* **Data structure:** Vector – DTM grid, Contour lines
* **Coverage:** Great Britain
* **Scale:** 1:50 000
* **Format:** GML 3.2 Simple Features, ASCII (DTM grid), ESRI Shapefile, vector tiles, GeoPackage
* **Ordering area:** All of Great Britain
* **Publication months:** July
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We recommend you read the following guides:

* [Getting Started with GeoPackage](https://docs.os.uk/os-downloads/getting-started/getting-started-with-geopackage)
* [Getting Started with Vector Tiles](https://docs.os.uk/os-downloads/resources/product-resources/getting-started-with-geopackage-and-vector-tiles-guides/getting-started-with-vector-tiles)
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## How to get this product

Access to this OS OpenData product is free through the [OS Data Hub](https://osdatahub.os.uk/data/downloads/open/Terrain50).

## Sample data

### Visualise OS Terrain 50 sample data online

This product is available to try out free online using one of our three sets of sample data (Exeter, Newport and Inverness) through the OS MasterMap Product Viewer:

<table data-view="cards" data-full-width="false"><thead><tr><th></th><th></th><th data-hidden></th><th data-hidden data-card-cover data-type="image">Cover image</th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>OS MasterMap Product Viewer</strong></td><td>Interactive demonstrator of OS MasterMap Generation data</td><td></td><td data-object-fit="cover" data-alt="Example image showing OS VectorMap Local product data over an urban area."><a href="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2Fuld7V42IKrB8ovpC1JXB%2FVectorMap-Local-1.png?alt=media&#x26;token=cb3e8ae9-d669-4bc9-b7a7-5f479d780447">VectorMap-Local-1.png</a></td><td><a href="https://experience.arcgis.com/experience/20981dabcb14402687dccb437a4a78fb/">https://experience.arcgis.com/experience/20981dabcb14402687dccb437a4a78fb/</a></td></tr></tbody></table>

## What's next?

To access additional documentation and resources relating to this product, please refer to the following:

<table data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-cover data-type="image">Cover image</th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><h4>Overview</h4></td><td>The overview introduces OS Terrain 50 and gives context for all users – highlighting key features, providing examples of uses, and listing details such as product accuracy, supply formats, etc.</td><td></td><td data-object-fit="cover" data-alt="Example image showing OS Terrain 50 product data. The image shows part of Scotland."><a href="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2FuFsHU1HtK9sSjgmwQtK5%2FTerrain-50-1.png?alt=media&#x26;token=221e8eea-783b-495e-89d5-51c0731769ae">Terrain-50-1.png</a></td><td><a href="os-terrain-50/os-terrain-50-overview">os-terrain-50-overview</a></td></tr><tr><td><h4>Technical Specification</h4></td><td>The technical specification provides detailed technical information about OS Terrain 50. It is targeted at technical users and software developers.</td><td></td><td data-object-fit="cover" data-alt="Example image showing OS Terrain 50 product data."><a href="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2Fv7XbGitWlRxrdHeL0KcH%2FTerrain-50-4Web.png?alt=media&#x26;token=76292066-b246-4554-91ab-a75e7674d1b6">Terrain-50-4Web.png</a></td><td><a href="os-terrain-50/os-terrain-50-technical-specification">os-terrain-50-technical-specification</a></td></tr><tr><td><h4>Ordnance Survey Website</h4></td><td>View OS Terrain 50 product information and find out how to get this product on the OS website.</td><td></td><td></td><td><a href="https://www.ordnancesurvey.co.uk/products/os-terrain-50">https://www.ordnancesurvey.co.uk/products/os-terrain-50</a></td></tr></tbody></table>

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New users should start with the Overview to gain high-level insight into the product. The Technical Specification contains detailed technical insights.
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