> 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/water-portfolio/os-open-rivers/os-open-rivers-technical-specification/code-lists/linkdirectionvalue.md).

# LinkDirectionValue

The [WatercourseLink](/os-downloads/products/water-portfolio/os-open-rivers/os-open-rivers-technical-specification/feature-types/watercourselink.md) feature is attributed with a *flowDirection* with a data type of *LinkDirectionValue*. The following table lists the codes which are used to populate this field and gives a description for each code.

{% hint style="info" %}
This code list is inherited from INSPIRE and is not extendable.
{% endhint %}

## **Code list: LinkDirectionValue**

List of values for directions relative to a link <http://inspire.ec.europa.eu/codelist/LinkDirectionValue/>

| Code                  | Description                            |
| --------------------- | -------------------------------------- |
| both directions       | In both directions.                    |
| in direction          | In the direction of the link.          |
| in opposite direction | In the opposite direction of the link. |

Where the flow direction has not been determined, this attribute is set to null and a *nilReason* is given:

* Where the value of *nilReason* is set to *unknown*, then the flow direction is not known to Ordnance Survey. A correct value may exist, but the methods employed by Ordnance Survey to date have not facilitated capture.
* Where the value of *nilReason* is set to *missing*, then the flow can be considered indiscernible. Ordnance Survey has attempted to identify the flow on the ground, but no flow has been determined.


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