Open OS MasterMap

Following the Government announcement to open OS MasterMap data, here’s a breakdown of the key points you need to know:

If you want to be involved in shaping the delivery please register your interest using the form below:

What is OS MasterMap and what will be released?

OS MasterMap is the definitive and authoritative source of detailed geographic data of Great Britain. Under the Open Government Licence (OGL) key parts of OS MasterMap are being made open. With the remaining data being made freely available up to a threshold, releasing £130m pa of economic value.

What is the full list of datasets being opened?

OS MasterMap will be made available for free, up to a threshold, through an API. This will include:

  • OS MasterMap Topography Layers, including building heights and functional sites
  • OS MasterMap Greenspace Layer
  • OS MasterMap Highways Network
  • OS MasterMap Water Network Layer
  • OS Detailed Path Network

In addition, key part of Ordnance Survey's (OS) highly detailed OS MasterMap are being made completely open under Open Government Licence (OGL).   This includes:

  • Property extents derived from OS MasterMap Topography Layer
  • Spatial identifiers:
    • OS MasterMap Topography Layer TOIDs (Topographic Object Identifiers) will be incorporated into the features in OS Open Map-Local
    • Over the next 12 months the Geospatial Commission will work with GeoPlace, LGA, the Improvement Service (on behalf of Scottish Local Government), and OS to investigate how best to open up the key identifiers UPRN and USRN, together with their respective geometries, for the whole of Great Britain under OGL terms. Due to the importance of these identifiers this will need to be done in a such a way that protects the integrity and authority of these identifiers, so as to provide both businesses and public-sector organisations the confidence to continue to rely on these within their own products and services, without restricting their ability to use and benefit from them.
What will the transaction threshold be?

The transaction threshold will be comparable to that increasingly available for similar APIs. This will be designed during the implementation phase, in consultation with the sector.

When will they be open?

The implementation project is expected to last 24 months with deliverables during this period. OS and the Geospatial Commission will work with the geospatial industry during the implementation period.

Will OS Explorer maps and OS Landranger maps still be available?

Ordnance Survey will continue to produce its iconic paper maps and maintain both the 1:25 000 and 1:50 000 scale data. These datasets are not included in the open data announcement.

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