Waterways in the United Kingdom
Mainland Britain has 3,000 to 4,000 miles of waterways that are commonly considered "navigable" by powered boats. Added to this are numerous derelict canals which can still be traced on the ground, and also many, many more miles of canoeable rivers. Many of the derelict canals or lost river navigations are active restoration projects with over 600 miles (>960km) having already been restored to navigation since the major restoration movement started in the 1960's.
OpenStreetMap began in London, and the River Thames flowing through London was one of the first places where we pondered the challenge of mapping large (also tidal) rivers in a way which allowed software to render it properly. The tidal section of the Thames was initially brought in by the coastline imports, and then traced from Landsat.
OSM-based waterway maps
- OpenRiverBoatMap is a European map but may not render UK waterways correctly due to tagging differences [NB OpenRiverBoatMap seems to have been offline for a while as of May 2021 and may not be being maintained any more]
What (and how) to map
The following tags are those in majority use in UK waterway mapping at the present time, as confirmed by Taginfo.
Navigable waterways are mapped as single ways like this:
For a tidal river, add
The direction of the way should be downstream. It should be drawn to follow the centre of the navigable channel.
Towpaths are mapped as footways or cycleways as usual, depending on their construction:
Many towpaths are nominally open to bikes, but haven't been adapted for use by them (for example, unimproved rural towpaths). Map these as highway=footway, bicycle=yes, towpath=yes to reflect the fact they're really just footways on which bikes are allowed.
Each lock should be a separate way, mapped like this:
- name=Trent & Mersey Canal
- lock_name=Branston Lock
- lock_ref=8 (the number of the lock, if it has one)
The first node should be the top gates, the second and last node the bottom gates: in other words, it points downstream.
Each lock gate node should also be given a tag:
Staircase locks can therefore be plotted simply by sharing lock-gate nodes.
- name=Dallow Lane (the road name as usual, not the bridge name)
- bridge:name=Dallow Lane Bridge (the name of the bridge)
- bridge:ref=32A (the bridge number)
If it's a private accommodation bridge over a rural canal, just tag it as a private track:
If it's a lift or swing bridge:
- name=Trent & Mersey Canal
- tunnel:name=Harecastle Tunnel
- maxwidth=7'0" (and maxheight for headroom, etc.)
Derelict canals are traditionally tagged in the UK as:
Unnavigable rivers can, of course, be tagged as:
You can tag the limiting dimensions of waterways, locks, or even winding holes:
Note that, on a bridge, the maximum length/width refers to traffic using the bridge itself (probably a road). So if you want to tag the maximum width or height of the waterway passing underneath, put that on the waterway, not the bridge.
- Water points: a node on the bank with waterway=water_point
- Winding holes: a node on the waterway with waterway=turning_point
- Elsan disposal amenity=sanitary_dump_station with sanitary_dump_station:basin=yes (see Feature page)
- Pump out: amenity=sanitary_dump_station with sanitary_dump_station:pump-out=yes (see Feature page)
- Fuel: waterway=fuel with fuel:diesel=yes
- (to add: showers, etc. etc.)
Moorings and marinas
Moorings can be tagged two ways:
- Add a point and tag mooring=yes with maxstay=48 hours, 7 days; etc.
- If you know the full extent of the mooring, add a line over the appropriate part of the canal bank and tag as in 1.
(As suggested here: http://canalmap.net/editing-openstreetmap)
Further tagging information