Product supply mechanism and options

OS MasterMap Topography Layer incorporates a web-based ordering system that allows users to order their initial data supply and any updates, obtain price estimates and view details of their holdings on demand. The product is supplied as an online download. You can download data in its various formats from the OS Data Hub.

Please note that some formats are only available via OS Orders, Ordnance Survey's legacy ordering system; these formats are indicated in the following table:

* Feature Validation Dataset (FVDS) and Change-Only Update (COU) available.

† Only available via OS Orders.

There are two main supply options available for OS MasterMap Topography Layer: Full Supply or COU.

Initial Supply refers to the first order of OS MasterMap Topography Layer that a user makes, which will contain all features for all the layers selected for the area covered by the order. Upon Initial Supply, users can select whether they would like to receive future data updates as COU (user receives only the tiles/features that have changed since the last update) or a Full Supply (user receives all tiles/features regardless of whether they have changed since the last product update). COU data contains new and updated versions of features (known as Inserts and Updates, respectively), and information about departed features (known as Deletes); any feature within the area covered by the order that has not undergone any change will not be supplied.

The advantage of taking a COU Supply rather than a Full Supply is that, if applied regularly, the amount of data that must be processed and loaded is much smaller with a COU Supply. Users may request updates of the latest changes in their AOI, at any time, using the online service. Updates can either be for specified AOIs or GB wide.