# OS Open USRN Technical Specification

## Product overview

OS Open USRN is an open dataset of all Unique Street Reference Numbers (USRNs) within [OS MasterMap Highways Network](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-mastermap-highways-network-fundamentals), with an associated simplified line geometry representing the geographic extent of each USRN.

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A USRN is a unique and persistent identifier for a street contained in either the National or Scottish Street Gazetteer. Every street, road, track, path, cycle track or way is assigned a USRN by a Roads Authority, Local Highway Authority or Highways England.
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This product has been designed to enable users to easily share information held against a USRN with a location and to link together information associated with USRNs, enabling location-specific visualisation and analysis.

<figure><img src="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2F7efrdCfilFx1MR1Y8mAb%2Fopen-usrn-datahub-1-large.png?alt=media&#x26;token=fdcc523e-3cd4-4178-a2b9-200e20a552ad" alt="A visualisation of the OS Open USRN dataset showing individual streets highlighted."><figcaption><p>A representation of OS Open USRN data against a background map.</p></figcaption></figure>

## Product structure <a href="#bookmark4" id="bookmark4"></a>

OS Open USRN is a vector dataset with a single line feature for each USRN. Each of these features will have accompanying attribution and a simplified line geometry.&#x20;

The following pages will detail the attribution held against the features in this dataset and provide further information about the source and simplification of the geometry.

## Index <a href="#bookmark5" id="bookmark5"></a>

This technical specification includes the following sections:

* [Street Type](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-open-usrn/os-open-usrn-technical-specification/street-type)
* [Feature type](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-open-usrn/os-open-usrn-technical-specification/feature-type)
* [Geometry](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-open-usrn/os-open-usrn-technical-specification/geometry)
* [Metadata](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-open-usrn/os-open-usrn-technical-specification/metadata)

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The [OS Open USRN Overview](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-open-usrn/os-open-usrn-overview) details what coordinate reference system is used by OS Open USRN and gives product supply information (including the available format, supply mechanism, coverage and currency).
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