> 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/~/changes/AJZwzCsyrD9hiTbOxIbO/networks/os-mastermap-water-network-layer.md).

# OS MasterMap Water Network Layer

{% embed url="<https://www.ordnancesurvey.co.uk/products/os-mastermap-networks-water-layer>" %}

OS MasterMap Water Network Layer is a three-dimensional digital representation of Great Britain's watercourses. The product includes rivers, streams, lakes, lochs and canals as a series of watercourse network lines. The network lines (links) are attributed to provide a range of information about the section of watercourse they depict. OS MasterMap Water Network Layer will significantly enhance systems used to manage waterways and rivers and the flood risk they pose.

{% hint style="info" %}
**This product is updated quarterly in January, April, July and October.**
{% endhint %}

<figure><img src="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2FrvnOU8QihHcoa3tDOsse%2Fimage.png?alt=media&amp;token=c3f640eb-ce25-40c6-ba03-6d5ab7e4b57d" alt="OS MasterMap Networks - Water layer map showing river networks over land"><figcaption><p>OS MasterMap Water Network Layer map.</p></figcaption></figure>

{% tabs %}
{% tab title="Features" %}

#### **Content and context**

With this water network data, you can look up the height of any watercourse, along with its flow direction, gradient, length and width anywhere along its length.

#### **Precise watercourses details**

As an island, water defines Great Britain. No other visualisation of our nation’s watercourses details the heights of watercourses in relation to sea level with this level of precision.

#### **Complete picture in 2D and 3D**

For planners, for surveyors, for engineers – this layer offers the potential to model in 2D and 3D like never before, thanks to the clarity of river flow, gradient and river widths.

#### **Answers on tap**

From aqueducts to tunnels, with annotations of flow direction, OS MasterMap Water Network Layer provides useful detailed mapping that includes underground watercourses (inferred from entry and exits).

#### **Detailed centre line**

OS MasterMap Water Network Layer provides a detailed centre line following the curve of the waterway precisely. It includes the coordinates of watercourse sources and where they meet, exactly.
{% endtab %}

{% tab title="Summary" %}

* **Access**: Download
* **Category**: Networks
* **Data theme**: Water
* **Data structure**: Vector – Topologically structured link and node network
* **Coverage**: Great Britain
* **Scale**: 1:1 250 to 1:10 000
* **Format**: GML 3.2.1, GeoPackage, vector tiles
* **Ordering area**: All of Great Britain or customisable areas (5km² tiles)
* **Publication months**: January, April, July, October
* **OS Data Hub plan**: Energy & Infrastructure Plan, Premium Plan, Public Sector Plan
  {% endtab %}
  {% endtabs %}

## How to get this product

Access to this product is free for Public Sector Geospatial Agreement (PSGA) Members. Find out if you are a PSGA Member or download a sample of OS MasterMap Water Network Layer data by accessing the [product page on the OS website](https://www.ordnancesurvey.co.uk/products/os-mastermap-networks-water-layer#get), which has links to all of the relevant resources. Alternatively, you can try out the full product by applying for [a Data Exploration license](https://www.ordnancesurvey.co.uk/licensing/data-exploration-licence).

## Visualise OS MasterMap Water Network Layer data online

This product is available to try out online using one of our three sets of sample data (Exeter, Newport and Inverness) through the OS MasterMap Product Viewer:

<table data-view="cards" data-full-width="false"><thead><tr><th></th><th></th><th data-hidden></th><th data-hidden data-card-cover data-type="files"></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>OS MasterMap Product Viewer</strong></td><td>Interactive demonstrator of <mark style="color:purple;">OS MasterMap Generation</mark> data</td><td></td><td><a href="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2Fuld7V42IKrB8ovpC1JXB%2FVectorMap-Local-1.png?alt=media&amp;token=cb3e8ae9-d669-4bc9-b7a7-5f479d780447">VectorMap-Local-1.png</a></td><td><a href="https://experience.arcgis.com/experience/20981dabcb14402687dccb437a4a78fb/">https://experience.arcgis.com/experience/20981dabcb14402687dccb437a4a78fb/</a></td></tr></tbody></table>

## # Other ways to access this data

MasterMap Water Network Layer data is available from our [OS Features API](https://docs.os.uk/os-apis/accessing-os-apis/os-features-api), providing location-based insights combining topography data with buildings, transport, and water layer data to create finely detailed datasets with a high degree of accuracy. Find out more about our [OS API platform here](https://docs.os.uk/os-apis) to unlock access to rich geospatial data and integrate OS data and services into your applications.

Access to MasterMap Water Network Layer data is also available through the [OS NGD Water Theme](https://docs.os.uk/osngd/data-structure/water),  providing a three-dimensional structured link and note network of watercourses for Great Britain. Users may find that NGD Water Theme data is more accessible, contains greater attribution, and is easier to use with databases and GIS software. Find out more about [NGD data here](https://docs.os.uk/osngd) to discover how to access OS NGD and what's available to users.

## What's next?

To access additional documentation and resources relating to this product, please refer to the following:

<table data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-cover data-type="files"></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><h2>Overview</h2></td><td>The overview introduces OS MasterMap Water Network Layer and gives context for all users – highlighting key features, providing examples of uses, and listing details such as file sizes, etc.</td><td></td><td><a href="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2F0uuBdYg4IlxB3ptTMCiP%2FMasterMap-Water-Network-5.png?alt=media&amp;token=b043504c-d8c7-4cd8-a552-77e799626fe6">MasterMap-Water-Network-5.png</a></td><td><a href="/os-downloads/~/changes/AJZwzCsyrD9hiTbOxIbO/networks/os-mastermap-highways-network-core-principles/os-mastermap-highways-network-overview.md">OS MasterMap Highways Network Overview</a></td></tr><tr><td><h2>Getting Started Guide</h2></td><td>The getting started guide provides instructions for using OS MasterMap Water Network Layer in different applications. Users with limited technical knowledge will be able to follow this guide.</td><td></td><td><a href="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2FY6Jh7dMYdgfFt39h0rNu%2FMasterMap-Water-Network-2.png?alt=media&amp;token=dca348b7-7a38-4274-93c5-1355437b3aa8">MasterMap-Water-Network-2.png</a></td><td><a href="/os-downloads/~/changes/AJZwzCsyrD9hiTbOxIbO/networks/os-mastermap-water-network-layer/os-mastermap-water-network-layer-getting-started-guide.md">OS MasterMap Water Network Layer Getting Started Guide</a></td></tr><tr><td><h2>Technical Specification</h2></td><td>The technical specification provides detailed technical information about OS MasterMap Water Network Layer. It is targeted at technical users and software developers.</td><td></td><td><a href="https://1897589978-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FcNpJpLP8RROUaWVQo5ea%2Fuploads%2FqlKAdkK0alzXzbKGwrUM%2FMasterMap-Water-Network-1.png?alt=media&amp;token=f2ba6610-d4ee-456e-abae-43639afa48f3">MasterMap-Water-Network-1.png</a></td><td><a href="/os-downloads/~/changes/AJZwzCsyrD9hiTbOxIbO/networks/os-mastermap-water-network-layer/os-mastermap-water-network-layer-technical-specification.md">OS MasterMap Water Network Layer Technical Specification</a></td></tr></tbody></table>

{% hint style="info" %}
New users should start with the Overview to gain high-level insight into the product. The Getting Started Guide will help you to begin using product data in different software systems. The Technical Specification contains detailed technical insights.
{% endhint %}


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