# OS Open TOID Documentation

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.

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**This product is updated every six weeks (in-line with the** [**OS MasterMap Topography Layer**](https://docs.os.uk/os-downloads/products/buildings-and-infrastructure-portfolio/broken-reference) **releases).**
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<figure><img src="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2FzqzREBnCTFHoLtSoQIny%2Fopen-toid-data.xdc094ecd%20(1).webp?alt=media&#x26;token=427552bf-c664-4997-be13-a003716e0932" alt="Representation of OS Open TOID data against a background map. The TOIDs are represented by red dots (point data)." width="563"><figcaption><p>Representation of OS Open TOID data with a background map included for context.</p></figcaption></figure>

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OS Open TOID is part of the OS Open Identifiers 'Family' of products, which includes four OpenData products: OS Open Linked Identifiers, OS Open TOID, OS Open UPRN and OS Open USRN. The products within this family allow you to easily share information held against a range of identifiers and to link together information associated with these identifiers.
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{% tab title="Benefits" %}
**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](https://docs.os.uk/os-downloads/products/buildings-and-infrastructure-portfolio/broken-reference) and [OS MasterMap Sites Layer](https://docs.os.uk/os-downloads/products/land-and-terrain-portfolio/os-mastermap-sites-layer) products and all of the junctions, roads and paths present in the [OS MasterMap Highways Networks](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-mastermap-highways-network-fundamentals) 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.
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{% tab title="Use Cases" %}
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](https://docs.os.uk/os-downloads/products/buildings-and-infrastructure-portfolio/broken-reference) 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.
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{% tab title="Summary" %}

* **Access:** Download via the [OS Data Hub](https://osdatahub.os.uk/)
* **Data theme:** Multiple
* **Data structure:** Vector – Identifiers
* **Coverage:** Great Britain
* **Scale:** 1:1 250 to 1:10 000
* **Format:** GeoPackage, CSV
* **Ordering area:** Customisable area (100km² tiles)
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{% tab title="Additional Information" %}
**TOID features**

The register for TOIDs is not exhaustive. Not all TOID features are included in the product as some feature types are not useful for third-party data references; however, all TOIDs are provided for every feature type we have included in the product.

**TOID geometry**

TOID geometry always lies within the polygon. We are using a pole of inaccessibility algorithm to selection a generalised point location for polygon which can be used to position a label for that feature. The aim is to provide a point which is most suitable for labelling the polygon. In the situation where we have a multi-polygon feature (only found in our [OS MasterMap Sites Layer](https://docs.os.uk/os-downloads/products/land-and-terrain-portfolio/os-mastermap-sites-layer) product), the point is placed in the largest polygon.
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## How to get this product

Access to this OS OpenData product is free through the [OS Data Hub](https://osdatahub.os.uk/data/downloads/open/OpenTOID).

## What's next?

To access additional documentation and resources relating to this product, please refer to the following:

<table data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-cover data-type="image">Cover image</th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><h4>OS Open Identifiers Family Information</h4></td><td>This page gives context and information about the OS Open Identifiers 'Family' of products, including explaining what identifiers are and introducing the OS identifiers (TOID, UPRN and USRN).</td><td></td><td data-object-fit="cover" data-alt="OS Open Linked Identifiers diagram showing the interconnected relationship in the product between TOIDs, UPRN, USRNs, and GUID."><a href="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2FevuHYX9cyID9OYhzPVGe%2FLinked_identifiers_Cover.avif?alt=media&#x26;token=5d07dde3-8aeb-4930-9526-e5d5487c8306">Linked_identifiers_Cover.avif</a></td><td><a href="../addresses-and-names-portfolio/os-open-uprn/os-open-uprn-overview/what-is-an-identifier">what-is-an-identifier</a></td></tr><tr><td><h4>Overview</h4></td><td>The 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.</td><td></td><td data-object-fit="cover" data-alt="Example image showing OS Open TOID product data over a background map."><a href="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2FzqzREBnCTFHoLtSoQIny%2Fopen-toid-data.xdc094ecd%20(1).webp?alt=media&#x26;token=427552bf-c664-4997-be13-a003716e0932">open-toid-data.xdc094ecd (1).webp</a></td><td><a href="os-open-toid/os-open-toid-overview">os-open-toid-overview</a></td></tr><tr><td><h4>Technical Specification</h4></td><td>The technical specification provides detailed technical information about OS Open TOID. It is targeted at technical users and software developers.</td><td></td><td data-object-fit="cover" data-alt="Example image showing OS Open TOID product data over a background map."><a href="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2F1vEoFLMW7DrzGpVc8b2W%2Fopen_toids_highways_web.png?alt=media&#x26;token=62c48b8b-ff54-4e1a-a3bb-d23faf1ce5bb">open_toids_highways_web.png</a></td><td><a href="os-open-toid/os-open-toid-technical-specification">os-open-toid-technical-specification</a></td></tr><tr><td><h4>Ordnance Survey Website</h4></td><td>View OS Open TOID product information and find out how to get this product on the OS website.</td><td></td><td></td><td><a href="https://www.ordnancesurvey.co.uk/products/os-open-toid">https://www.ordnancesurvey.co.uk/products/os-open-toid</a></td></tr></tbody></table>

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New users should start with the Overview to gain high-level insight into the product. The Technical Specification contains detailed technical insights.

We recommend referring to the OS Open Identifiers Family information page in combination with the Overview and Technical Specification documents for OS Open TOID.
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