What is a TWUID?

A track's TWUID is its TrailWise2 Unique IDentification number.

TWUIDs are simply a method of labelling track sections. The TWUID provides a consistent way of numbering track lengths that can be calculated from the position of that track. Remember that any route or green lane may be made up from a number of track lengths, connecting at junctions or other significant points.

The TWUID consists of two parts: a two letter and four digit geographic ID, and a two digit suffix. The geographic ID part is simply the OS reference for the 1km grid square containing the most westerly or southerly end of the track, e.g. if a track runs east from grid ref ST 235 787 its TWUID would begin ST2378.

More than one track section may start within the same 1km square, so a two-digit number is appended to the geographic ID to make sure it is unique, to give the full TWUID, ST2378-02 for example.

Although the TWUID is based upon the Ordnance Survey National Grid System, it does not fully describe the location of a route to a sufficient extent to establish where both the start and end of that route are located.