# OS Open Rivers Overview OS Open Rivers provides a two-dimensional, topologically-structured link-and-node network of Great Britain’s watercourses. A link represents the approximate central alignment of a watercourse. Attribution indicates the flow direction and name of each watercourse. OS Open Rivers is a generalised product which is automatically derived from Ordnance Survey large-scale data. The nominal usage scale is 1:25 000, with a recommended viewing scale range of 1:15 000 to 1:30 000. ## Key features The key features of the OS Open Rivers product are as follows: * Comprehensive coverage of Great Britain's river network. * A topologically-structured link-and-node network. * Water flow direction information. * Classified links which allow you to identify the differences between tidal and inland rivers.
Illustrative map image of OS Open Rivers and its associated attribution.

Illustrative image of OS Open Rivers and its associated attribution.

## Applications OS Open Rivers supports a wide range of applications that use geographic information. The product can be used alone or in combination with other Ordnance Survey products, such as [Terrain 50](/os-downloads/products/land-and-terrain-portfolio/os-terrain-50.md) or [VectorMap District](/os-downloads/products/maps-and-imagery-portfolio/os-vectormap-district.md). OS Open Rivers has numerous applications, including but not limited to, the following examples: * Relating information to the river network for both personal and business use * Simple analytical queries (for example, the overall lengths of larger rivers in Great Britain) * Simple planning around main watercourses using the detailed connectivity and flow (from source to mouth) information * Regional-level environmental impact assessments (for example, an indication of what towns have rivers passing through them) * Backdrop mapping It is important to note that detailed analysis is not supported in OS Open Rivers; this requires the additional detail and complexity available in data from the [OS National Geographic Database (OS NGD) Water Theme](https://docs.os.uk/osngd/data-structure/water). --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.os.uk/os-downloads/products/water-portfolio/os-open-rivers/os-open-rivers-overview.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.