> 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-overview.md).
# OS Open Rivers Overview
This overview introduces OS Open Rivers and gives context for all users – highlighting key features, providing examples of uses, and listing details such as file sizes, supply formats, etc.
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 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).
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