OS MasterMap

OS MasterMap, provided by Ordnance Survey, is a digital representation of Great Britain containing more than 450 million uniquely identified geographic features. It is updated daily as a consistent framework for the referencing of geographic information in Great Britain. It is available in several data layers. First, the OS MasterMap Topography Layer is Ordnance Survey’s flagship large-scale, polygonized, and seamless topographic database product. It is the most flexible and intelligent topographic information the Ordnance Survey has ever provided. Second, the OS MasterMap Integrated Transport Network (ITN) Layer provides the national definitive and intelligent multimodal transport network dataset for Great Britain. The third data layer is OS MasterMap Address Layer 2, which provides precise postal address coordinates across Great Britain and contains a range of new data such as objects without postal addresses (OWPAs), multioccupancies without postal addresses (MOWPAs), alternative geographic/Welsh addresses, and building name aliases. OS MasterMap Address Layer is also available. Last, the OS MasterMap Imagery Layer is supplied to customers as ready-to-use, color-balanced, and fully edgematched orthorectified color aerial imagery data.

Courtesy of Ordnance Survey, Crown copyright 2007.