OS Terrain 5: Shapefile Contours - GML Contours - ASCII Grid

If you are using OS MasterMap Topography Layer, you will not find another height product with this level of consistency and currency:

- Understand and communicate the visual impact of planned development

- Plan coastal protection measures and model what-if scenarios with confidence

- Get your message across with real-world, three-dimensional modelling

- Analyse wind speed, signal propagation and flood risk

- Identify gradients and access to planned developments for transport and utilities infrastructure

Unrivalled currency

OS Terrain 5 is regularly updated from the same source imagery as Ordnance Survey large-scale data. This ensures that their representation of changes to real world features are synchronised across thier product portfolio.

Targeted accuracy

Explicit modelling of significant landscape features such as roads, railways, slopes, quarries and lakes and a typical accuracy exceeding 2 m RMSE ensures a reliable representation of high-value features throughout Great Britain.

OS Terrain 5 Specifications

Format	GML 3.2 and ASCII grid for DTM, GML 3.2 and Esri shapefile for contours
Resolution	Grid: 5m post spacing. Contours: vertical interval of 5m.
Tile size	5km x 5km
Scale	1:10000 - works well with large scale data (OS Mastermap)
Supply	FTP, DVD, CD or USB (depends on quantity ordered)
OS Update frequency	Quarterly
Coverage	UK (excluding NI), Scotland, England, Wales available or select individual tiles

The delivery of OS terrain 5 has been designed to offer both grid and contours for one price to save you having to manage separate product orders and licences. There is a choice of contour formats so you select the type of contours you wish to receive. You will receive links to both grid and contours but are not forced to download any data formats that you do not want. However if you just want grid you do need to choose a contour type to complete the order as the product offers both formats for one price.

Customers who are using other Ordnance Survey data products will not find another height product in the market that offers this level of consistency, coverage and currency with Ordnance Surveys topographic features. It is more than a product on its own, but a fully integrated part of the Ordnance Survey data stack:

Both grid and contours are available for one price;

Major roads, rail and large water bodies have been modelled with superior accuracy for better results in modelling applications;

OS Terrain 5 will be updated on a quarterly basis.

Revision frequency is planned to take place on a 3-5 year rolling cycle synchronised with OS large-scale data.

No, OS Terrain products originate from a completely new capture flowline designed to use imagery flown for our large-scale products to produce height data for a new height content store. The store has been designed as the base for our 3D strategy to enable the height data to be used throughout our portfolio and for new products in the future.

They are contained within the gml file and located here:

OS Terrain Grid Products

OS Terrain Contour Products

In OS Terrain, the mean high and mean low water lines have been assigned constant height values, based on the average for each tile from information sourced from tide tables. These values have been continued offshore up to the tile edge to ensure consistency (but do not affect the onshore values).

Due to local tidal conditions, the height of the mean high and low water mark varies continuously around the coast of Britain. Inevitably, this means that there can be a step from the tidal area between adjacent tiles. If you wish to remove this detailed information and apply other values for the sea you can select the mean high and low water boundaries from the contour product and use them as a bounding box.

OS have ensured additional modelling for features that are often used for analytical applications – such as such as major communication routes, lakes, quarries and urban areas. See the example below with the motorway network and Killington Reservoir.