[OSM-talk] Mapping Canals

[Gervase Markham]

Based on the discussion from a few weeks ago, I've made a number of new 
proposals relating to canals which are now listed on the Proposed 
Features page at the bottom of various categories:

http://wiki.openstreetmap.org/index.php/Proposed_features#Proposed_Features_-_Waterway
http://wiki.openstreetmap.org/index.php/Proposed_features#Proposed_Features_-_Amenities
http://wiki.openstreetmap.org/index.php/Proposed_features#Keys
http://wiki.openstreetmap.org/index.php/Proposed_features/Potable_Water
http://wiki.openstreetmap.org/index.php/Proposed_features/Lock
[David Earl: do shout if you think I've butchered your Lock proposal.]

My own draft Right Way of Doing Things, which incorporates the 
proposals, is below for your reference.

Gerv

<snip>

Note: canal measurements are given in feet and inches, as "\d+ft( 
\d+in)?". That is, a number, followed by "ft" as an abbreviation, a 
space, and then optionally a number and "in".

Canals
------

Canals are denoted by a single way (rather than two banks), whose 
direction is irrelevant except in the case of locks or significant water 
flow.

The entire section of canal (between two junctions) is tagged with 
maxlength and maxwidth, representing the largest boat which can travel 
along that section of the canal.

Narrow sections are denoted by "narrows=yes". Bridge holes are implied 
narrow, and don't need explicit marking.

Cuttings and embankments are shown only when they apply to both sides of 
the canal, in which case the relevant part of the way has "cutting=yes" 
or "embankment=yes". (This is a slight simplification compared to 
existing maps.)

Winding holes are marked as nodes in the canal with 
"waterway=turning_point"; the max length of boat which can be winded is 
denoted using "maxlength" on the node, even though this is a small 
stretch of the meaning.

"access=private" is used for "private" parts of the canal (that is, 
parts which are not accessible to all licensed boaters). "boat=private" 
is deprecated.

Canals are, by default, level=0 (i.e. no level tag).

If not operated by BW, indicate operator using "operator=Foo Corp".

Locks
-----

(See wiki page: 
http://wiki.openstreetmap.org/index.php/Proposed_features/Lock)

The wiki page makes some good points, but I suggest we have *both* 
"waterway=lock_gate" on nodes (useful for large locks, optional for 
small ones) and "lock=yes" on canal/river ways (compulsory, easy to render).

The "lock=yes" way(s) points from the higher to the lower end of the 
lock, i.e. in the direction of water flow. So the lock "arrow" symbol 
would point in the opposite direction.

The "lock=yes" way(s) takes various lock-related information, including:

- the lock name, if it has one, with "name=<foo>".
   XXX clash with waterway name?
- the maxwidth, with "maxwidth=Xft Yin".- the maxlength, with 
"maxlength=Xft Yin".
- the rise, with new tag "rise=Xft Yin".

A flight of locks with a unifying name (e.g. "Hatton Locks") is denoted 
by a relation. XXX need more detail

Moorings
--------

Mooring info should be attached to the relevant stretch of towpath, or 
to a new dedicated way on the opposite side, for the rare offside 
moorings. "mooring=yes/private/no" should be used, applied to ways 
rather than nodes. Only explicitly marked mooring conditions should be 
shown. Renderers may choose to render the way as an icon placed at the 
centre of the length.

"waterway=mooring" is deprecated, to be replaced with the above, as it's 
not an actual waterway receiving the tag. (We couldn't tag the canal 
itself this way anyway, as it's already "waterway=canal".)

New tag: maxstay=<days>. Overnight is "1". This is applied to all of the 
way(s) tagged with "mooring=yes".

If the mooring must be paid for, add "cost=paid"
http://wiki.openstreetmap.org/index.php/Proposed_features/Price_tags

Aqueducts
---------

waterway=aqueduct is replaced with aqueduct=yes (and we probably should 
make the same change for viaducts), and should be used just like a 
bridge tag.

Bridges
-------

New tag: ref_bridge=<number> for bridge numbers.

New tag: bridge_type=manual_swing, powered_swing, ....

Towpaths
--------

The towpath is shown as another way alongside the canal, on the 
appropriate side, with new tag "towpath=yes". It is continuous as long 
as the towpath is; if the towpath switches sides, the way connects into 
the relevant bridge, which also has "towpath=yes".

Nodes which are part of the path can take info like water_point, etc. 
Like any path, it can take quality and access tags.

Mile markers are denoted as towpath nodes with new tag value: 
"distance_marker=<text>/yes".
http://wiki.openstreetmap.org/index.php/Proposed_features/Distance_Marker

Amenities
---------

Some changes for consistency:
Change: waterway=waste_disposal -> amenity=waste_disposal
Change: waterway=water_point -> amenity=drinking_water
http://wiki.openstreetmap.org/index.php/Proposed_features/Potable_Water

Make sure amenity=waste_disposal is clearly defined as a refuse point.

New tag value: amenity=pumpout
New tag value: amenity=sanitary_station
(Self-operated or not? XXX)
See also 
http://wiki.openstreetmap.org/index.php/Proposed_features/Dump_Station