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OS MasterMap Topographic Identifiers – TOIDs

Learn about the criteria according to which we update different features and areas in our large-scale products, notably OS MasterMap Topography Layer.

What is a TOID?

A TOID is a unique identifier, consisting of the letters ‘osgb’ and followed by up to sixteen digits, associated with every feature*1 in many of Ordnance Survey’s large scale products. The TOID is based upon the Digital National Framework concept and the principles that underpinned it. The TOID contains no attribution or information (for example coordinate position) about the feature, nor can information be derived from either the allocated number or the process by which it is allocated. The TOID will remain with the feature throughout the feature’s life and will not be reassigned to a new feature when the existing feature is deleted.

TOID policy

Pending implementation of the Open MasterMap Programme, Ordnance Survey is temporarily suspending the policy previously available on this web page regarding the sharing and use of TOIDs. And in the meantime, any use of TOIDs is subject to the terms and conditions of the relevant licence. OS will review this statement in relation to TOIDs on the earlier of 31 December 2019 or implementation of the Open MasterMap Programme. 

*1 A ‘feature’ is any feature in a dataset representing a real world phenomenon. It may have a geometric property, including without limitation any line, point, polygon, symbol or text or it may have implied geometry by virtue of its relationship to other features.

It has a spatial domain (attribute), a temporal domain, or a spatial/temporal domain as one of its attributes. Examples of features include almost everything that can be placed in time and space, including desks, buildings, cities, trees, forest stands, ecosystems, delivery vehicles, snow removal routes, oil wells, oil pipelines, oil spills and so on. Features are usually managed in groups as feature collections.

Updated: October 2019