> 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-mastermap-sites-layer/os-mastermap-sites-layer-technical-specification/enumerations/extentdefinitionvalue.md).

# ExtentDefinitionValue

### FunctionalSite feature

Defines the values for the nature of extent that a particular site may have.

| Value             | Description                                                                                                                                                 |
| ----------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Fully Defined     | The supplied extent is, as far as can be ascertained, fully defined in this release.                                                                        |
| Partially Defined | The extent is known to be incomplete due to a known issue with the extent or because of restrictions to capture.                                            |
| Undefined         | The extent is unknown or has not been defined in this release. This will also apply to sites where their full definition is underground or wholly obscured. |


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