> 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/land-and-terrain-portfolio/os-open-greenspace/os-open-greenspace-technical-specification/data-structure.md).

# Data structure

The data structure of OS Open Greenspace in Geography Markup Language (GML) format is described by a Unified Modelling Language (UML) class diagram and accompanying tables containing text.

## Precision <a href="#bookmark2" id="bookmark2"></a>

OS Open Greenspace geometry is published with a precision of two decimal places.

## Classification scheme <a href="#bookmark3" id="bookmark3"></a>

OS Open Greenspace consists of the following classifications:

* Public parks or gardens
* Play spaces
* Golf courses
* Sports areas or playing fields
* Churchyards or burial grounds
* Allotments or community growing spaces

A full table of these classifications and associated Ordnance Survey real-world terms and their definitions is included in the [Function Value Code List](/os-downloads/products/land-and-terrain-portfolio/os-open-greenspace/os-open-greenspace-technical-specification/code-lists/functionvalue.md).

## Model overview <a href="#bookmark4" id="bookmark4"></a>

<figure><img src="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2FtYTDwv7rHyqwOYNvwyMj%2F2.png?alt=media" alt="Figure 2: UML class diagram for the Greenspace Site and Access Point Feature Types, and the Function Value and Access Type Value Code Lists"><figcaption><p>UML class diagram for the Greenspace Site and Access Point Feature Types, and the Function Value and Access Type Value Code Lists.</p></figcaption></figure>


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