OS Open TOID Overview

This overview introduces OS Open TOID and gives context for all users – highlighting key features, providing examples of potential uses, and listing details such as supply formats, currency, etc.

OS Open TOID is an open dataset of unique identifiers – Topographic Identifiers (TOIDs) – assigned by OS to real-world features extracted from the following three OS MasterMap products:

• OS MasterMap Topography Layer

  • TopographicArea

  • TopographicLine

  • TopographicPoint

• OS MasterMap Sites Layer

  • SiteExtent

• OS MasterMap Highways Network – Roads

  • RoadNode

  • RoadLink

  • PathLink

This product allows users to share and link information related to a wide range of landscape and built environment features with a unique identifier and generalised location which will allow them to be used easily by everyone.

TOIDs are unique and persistent identifiers, assigned by OS, for real-world features that have a physical presence in the world around you, such as a building or a road. A TOID consists of the letters ‘osgb’ and either 13 or 16 digits between 0 and 9. The TOID is allocated sequentially when a feature is created by Ordnance Survey and is never reassigned to a different feature.

For the TOID to be fully effective, it is essential that the OS-appointed TOID reference is not altered in any way.

OS Open TOID provides the identifiers for these features along with their generalised location:

• Point features: The original location rounded to the nearest metre.

• Line features: The midpoint of the line rounded to the nearest metre.

• Polygons features: Use a point of inaccessibility algorithm to find a point that is guaranteed to be within the polygon which is farthest from all edges; this location is then rounded to the nearest metre.

• Multi-polygon features (SiteExtent): Use the same method as for polygon features on the largest of the polygons.

Visualisation of OS Open TOID data showing three unique features and their associated metadata.

Key features

The key features of the OS Open TOID product are:

• The comprehensive inclusion of all Ordnance Survey’s capture of the physical features across Great Britain.

• Access to our unique topographic identifiers, allowing you to link to the OS MasterMap products.

• A guide to which products the features are sourced from.

• The ability to reference between a feature and qualitative data using a unique identifier.

Product applications

OS Open TOID offers a range of opportunities to link and share disparate datasets against a unique identifier, with a location.

For example, a local authority may use OS Open TOID to link unaddressed buildings captured within OS MasterMap Topography Layer with information such as ownership or planning permission to build a richer picture of land and property in their remit.

OS Open TOID is a dataset that is designed to use the OS MasterMap product family as a basis with which you can create your own rich, comprehensive dataset that caters to your specific needs. It is not designed to be used as a geospatial selector for features.

Visualisation of OS Open TOID data showing three unique road node features and their associated metadata.

Index

This overview includes the following sections:

• What is an identifier?

• Product supply

• Coordinate reference system