> For the complete documentation index, see [llms.txt](https://docs.os.uk/osngd/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/osngd/code-lists/code-lists-overview/waterlinkwidthderivationmethodvalue.md).

# waterlinkwidthderivationmethodvalue

This code list is used in association with the Width Derivation Method attribute which is present within the Water Link Feature Type. The code list describes how the Width Average, Width Minimum and Width Maximum attribute values are derived, for example, Calculated from Polygon or Modelled From Network.

| Label                               | Definition                                                                                                                                                                                      |
| ----------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Calculated From Polygon             | For Water Links which represent a body of water captured as a topographic area feature, calculations of average, minimum and maximum widths are based on the topographic area feature geometry. |
| Modelled From Network               | For Water Links which represent a water feature captured as a topographic line feature, average width is a modelled width based on the upstream and downstream characteristics of the network.  |
| Default Value For Geographic Region | For Water Links captured as a topographic line feature (where no width has been processed), average width is a default width based on the capture specification.                                |


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