OS Open TOID
This open dataset shows unique identifiers for a wide range of landscape and built environment features with a generalised location extracted from OS MasterMap products. A TOID (Topographic Identifier) is a unique and persistent identifier for each and every feature found in OS MasterMap products.

Authoritative identifiers for real-world objects
TOIDs (Topographic Identifiers) are the authoritative identifier assigned to and uniquely identifying real-world objects, being essential for customers to link their own data to and track change over time.
Easy to share
OS Open TOID enables data to be shared for a wide range of landscape and built environment features by providing these features with a unique identity and generalised location that can be used by everyone.
Complete topographic data
All of the topographic points, lines and polygons present in the OS MasterMap Topography Layer and OS MasterMap Sites Layer products and all of the junctions, roads and paths present in the OS MasterMap Highways Networks products are also part of OS Open TOID.
Authoritative source
The TOIDs in OS Open TOID are allocated by Ordnance Survey. This means you can have confidence you’re accessing an authoritative source of these identifiers.
Identifiers you can trust
The TOID is never reused as once it's allocated to a feature, that’s it; it will never change or be reused.
How to get this product
Access to this OS OpenData product is free through the OS Data Hub.
What's next?
To access additional documentation and resources relating to this product, please refer to the following:
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