Proposal:Tag:natural=rock overhang

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Tag:natural=rock_overhang
Proposal status: Draft (under way)
Proposed by: aharvey
Tagging: natural=rock_overhang
Applies to: node, way, area
Definition: A rock overhang is a shallow cave-like opening at the base of a bluff or cliff, which may be used as a place to protect against bad weather conditions.
Statistics:

Draft started: 2020-10-26
RFC start: 2020-10-26

Proposal

A rock overhang is a shallow cave-like opening at the base of a bluff or cliff, which may be used as a place to protect against bad weather conditions. https://en.wikipedia.org/wiki/Rock_shelter not https://en.wikipedia.org/wiki/Overhang_(rock_formation).

Distinct from a natural=cave_entrance which may offer no shelter or cliff. A cave entrance leads to an underground cavity that may go on for quite some distance, in comparison a rock overhang is filled with natural light and provides shelter from rain and wind.

Rock overhangs could be mapped as either a node, linear way or area way.

When mapped as a simple node ideally the natural=rock_overhang tag should be placed on a node part of the natural=cliff way, where the rock overhang is at the base of a cliff.

When mapped as a linear way the natural=rock_overhang tag should share the natural=cliff way for the section of the rock overhang, when is at the base of a cliff.

When mapped as a closed way, part of the way should share the natural=cliff way for the section of the rock overhang, when is at the base of a cliff.

Sometimes a rock overhang would lead to a cave entrance at the deep end of the shallow, in which case you'll need to have a separate node for the natural=cave_entrance.

Rationale

shelter_type=rock_shelter is currently in use with 757 occurrences as of Sept 2020 according to https://taginfo.openstreetmap.org/tags/shelter_type=rock_shelter. It is currently documented as "A rock shelter is a shallow cave-like opening at the base of a bluff or cliff" and to be used as a subtype of amenity=shelter which is "a small place to protect against bad weather conditions".

In October 2020 it was proposed at Proposed features/Tag:shelter type=rock shelter however the proposal didn't reach a consensus and the opposing feedback had a common theme that amenity=shelter should be reserved for purpose built/man made shelters and not natural features commonly used as a place of shelter, with most opposition suggesting to use a natural=* tag instead.

While the current tag is documented on the amenity=shelter page and in use 757 times, there is significant community resistance to using this tag on talk-au and further discussed on tagging, and these features are extremely frequently mis-tagged as natural=cave_entrance.

natural=cave_entrance is the wrong tag for these rock overhangs/rock shelters as cave_entrance is "An entrance to a cave: a natural underground space large enough for a human to enter", a rock overhang is not like a cave, which is essentially an enclosed cavity with a small entrance opening. A cave you might need a torch to explore, a rock overhang is not like that.

Commonly these rock overhangs are named as "foobar Cave" and that may be why many are mis-tagged as cave entrances, but the name shouldn't have any input into the tagging. There are many other examples within OSM where we don't consider the name. eg McDonalds Restaurants are tagged as amenity=fast_food and not amenity=restaurant even though they might have "restaurant" in the name.

Examples

https://www.flickr.com/photos/136319147@N08/35519846196

Tagging

Applies to

Rendering

Features/Pages affected

External discussions

Comments

I'll leave this page open here for discussion for a few days, and then move to open voting to formalise this tag, but please refer to the existing discussions for further context.

Please comment on the discussion page.