> 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/buildings-and-infrastructure-portfolio/os-open-toid/os-open-toid-technical-specification/data-structure.md).

# Data structure

The OS Open TOID data carries five attributes which are all mandatory for each release. These can be used to identify and link affiliated information for a real-world object as well as plotting its real-world position. The TOID represents a range of feature types which related to an even wider range of real-world object types, examples range from buildings (including those without an address), roads, junctions, bridges, trees, fields and more.

## OS Open TOID attributes

### TOID

A unique identifier assigned to geospatial data by Ordnance Survey for their MasterMap products.

* **Type:** Varchar
* **Size:** 20
* **Multiplicity:** \[1]

### VERSION\_NUMBER

The date representing the version of the feature.

* **Type:** Integer
* **Size:** N/A
* **Multiplicity:** \[0 ... 1)

### VERSION\_DATE

The date representing the date the feature was last updated.

* **Type:** Datetime (GPKG), Date (CSV)
* **Size:** N/A
* **Multiplicity:** \[1]

### SOURCE\_PRODUCT

Attribute indicating which product a feature can be found in.

* **Type:** Varchar
* **Size:** 29
* **Multiplicity:** \[1]

### EASTING

A value in meters defining the x location according to the British National Grid.

* **Type:** Float
* **Size:** (precision, scale) - (10, 3)
* **Multiplicity:** \[1]

### NORTHING

A value in meters defining the y location according to the British National Grid.

* **Type:** Float
* **Size:** (precision, scale) - (10, 3)
* **Multiplicity:** \[1]

## GeoPackage structure <a href="#bookmark5" id="bookmark5"></a>

The GeoPackage data follows the same structure as demonstrated above, except for the inclusion of the following additional attribute:

#### id

A non-persistent integer which has been autogenerated as a function of OGC GeoPackage.

* Type: Integer
* Size: N/A
* Multiplicity: \[1]

GeoPackage is also split between three different layers to allow for easier data interrogation; these layers are:

* os\_mastermap\_highways\_network
* os\_mastermap\_sites\_layer
* os\_mastermap\_topography\_layer


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