# OS Open Linked Identifiers Getting Started Guide

OS Open Linked Identifiers is a dataset containing the authoritative relationships between Unique Property Reference Numbers (UPRNs), Unique Street Reference Numbers (USRNs) and Topographic Identifiers (TOIDs), and metadata. Identifiers are labels that are assigned to representations in a dataset. They are at the heart of how data can be effectively published, retrieved, reused and linked.

<figure><img src="/files/jYgPXcUVO1O7qeOuYSwh" alt="OS Open Linked Identifiers graph showing the relationship between TOIDs, UPRN, USRNs, and GUID" width="563"><figcaption><p>OS Open Linked Identifiers graph showing the relationship between TOIDs, UPRN, USRNs, and GUID</p></figcaption></figure>

OS Open Linked Identifiers enables you to connect the variety of relationships between UPRN, USRNs and TOIDs. These are synchronised with comprehensive premium products to provide you with the most up-to- date feature metadata sourced from AddressBase, OS MasterMap Highways Network and OS MasterMap Topography Layer. The more an identifier is used in other datasets, the more valuable the primary data becomes.

For example, OS Open Identifiers enables visualisation of data linked to the Highways RoadLink and Open Roads products. By sharing the road link mapping between Highways and Open Roads it enables data that has been collected and shared against the Highways’ premium products to be visualised in the open geometry.

Identifiers are crucial to the process of sharing information and linking together datasets, allowing them to fit into many workflows in many different types of workplace to provide powerful insights and support analytics.


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