> 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/maps-and-imagery-portfolio/os-mastermap-topography-layer/os-mastermap-topography-layer-technical-specification/complex-attributes.md).

# Complex attributes

A complex attribute is an attribute that consists of two or more simple attributes that go together to convey some composite information about a feature. They only exist within the GML format.

Further information on complex attributes in OS MasterMap Topography Layer is detailed in the following sub-pages.

<figure><img src="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2FVKZQqeDSl75XmQcO6zSY%2F9.jpeg?alt=media" alt="UML for the Change History Type Data Type in OS MasterMap Topography Layer." width="325"><figcaption><p>UML for the Change History Type Data Type in OS MasterMap Topography Layer.</p></figcaption></figure>

<figure><img src="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2F6IwBM2UOAcFsPdYB6csb%2F11.jpeg?alt=media" alt="UMLs for the Height Above Datum Type and Height Above Ground Level Type Data Types in OS MasterMap Topography Layer." width="563"><figcaption><p>UML diagrams for the Height Above Datum Type and Height Above Ground Level Type Data Types in OS MasterMap Topography Layer.</p></figcaption></figure>

<figure><img src="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2FPsUuwCwuLVbWS7dJXMQ5%2F10.jpeg?alt=media" alt="UML for the Text Rendering Type Data Type in OS MasterMap Topography Layer." width="221"><figcaption><p>UML for the Text Rendering Type Data Type in OS MasterMap Topography Layer.</p></figcaption></figure>


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