> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-downloads/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/os-downloads/products/transport-network-portfolio/os-mastermap-highways-network-paths/os-mastermap-highways-network-paths-technical-specification/structured-data-types/identifier.md).

# Identifier

The Identifier is an INSPIRE data type and its elements make up the “inspireId” attribute which can be found across all feature types in the OS MasterMap Highways Network.

## Identifier attributes

External unique object identifier published by the responsible body, which may be used by external applications to reference the spatial object.

### localId

The local identifier is unique within the namespace, that is no other spatial object carries the same unique identifier.

* **Attribute name:** localId (GML), local\_id (GeoPackage), Not provided (Vector Tiles)
* **Type:** CharacterString
* **Size:** 16
* **Multiplicity:** \[1]

### namespace

Namespace uniquely identifying the data source of the spatial object.

* **Attribute name:** namespace (GML), namespace (GeoPackage), Not provided (Vector Tiles)
* **Type:** CharacterString
* **Size:** 18
* **Multiplicity:** \[1]


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