OS Mastermap® Address Layer

The OS MasterMap Address Layer provides precise coordinates for more than 27 million residential and commercial properties in Great Britain – the most accurate and up-to-date link between any property address and its location on the map. The Address Layer originates from the Royal Mail's postcode address file (PAF®). Ordnance Survey uses on-the-ground GPS survey, aerial imagery and various other techniques to establish precise coordinates for each address and match this to the property on the map – effectively joining up postal and topographic geography, creating a fixed link between the property and its address.

Addresses are subject to a high level of change from:

* the creation of a new property;
* property redevelopment; and
* house or street name changes.

OS MasterMap Address Layer provides a robust mechanism for professional users to track and manage these address changes relating to the actual property on the ground, and a continuity between a physical property (essentially unchanging) and the dynamics describing that property (changeable).