[Tagging] Feature Proposal - RFC - Couloir

[Stefan Tauner]

There are already a number of related tags mentioned on the proposal
page explaining the major differences. While browsing I cam across
natural=earth_bank (https://wiki.openstreetmap.org/wiki/Tag:natural%3Dearth_bank),
which is clearly different and not that interesting but could be
mentioned.

However, I also found landform=* (https://wiki.openstreetmap.org/wiki/Key%3Alandform)
and thought I should bring that up as a possible alternative way to tag
couloirs. It is not used a lot (and is based on a Canadian import) but
it is clearly more specific than the quite overloaded natural=* key.
Nevertheless I think natural=couloir is the most natural way (SCNR) to
tag it.
-- 
Kind regards/Mit freundlichen Grüßen, Stefan Tauner