Proposed features/cliff clarification

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Clarify natural=cliff on closed ways and nodes
Status: Approved (active)
Proposed by: fkv
Tagging: natural=cliff
Applies to: Way Node
Definition: clarify the meaning of cliffs mapped as closed ways or nodes
Rendered as: line with ticks on right (=upper) side; on node: dot with surrounding ticks
Drafted on: 2014-08-22
RFC start: 2014-09-02
Vote start: 2014-12-30
Vote end: 2015-01-13

History

The tag natural=cliff was introduced in Mar 2006 in Map Features for Nodes and Areas, without any description or explanation. There was no changeset comment, and apparently there had not been any discussion in the Wiki, let alone a consensus. The first discussion entry in the wiki, dated Mar 2006, was an implicit request to use natural=cliff for ways. Nevertheless, the description "rock surface" was added to the Map Features page in Sep 2006. A voting on extending natural=cliff to linear features with the left side of the way meaning the upper side of the cliff was closed with a positive result in Mar 2008. Almost 2 years passed until that extension made it to the natural=* template in [http://wiki.openstreetmap.org/w/index.php?title=Template:Map_Features:natural&oldid=416371}}.

Meanwhile, there were some proposals to use natural=rock, natural=bedrock or natural=bare_rock for rock face. That may be the reason why the term "rock face" was removed from the natural=cliff description on Jun 2012. natural=cliff was approved in Aug 2012.

The Problem

natural=cliff is still defined for nodes, lines, and areas. The wiki does not specify what natural=rock means if set on nodes or areas. As an originally areal feature, natural=cliff on closed ways is still interpreted as an area by default by renderers such as Mapnik. However, they do not render those areas, because their meaning is in the dark.

A discussion of a ticket for default rendering style came to the conclusion that a clarification is needed in the Wiki.

Usage


Clarification Tasks/Questions

  1. Do natural=cliff on closed ways default to area=yes or area=no?
  2. What is the meaning of natural=cliff on areas?
  3. Do we want to deprecate them?
  4. What is the meaning of natural=cliff on nodes?
  5. Do we want to deprecate them?

Proposed Answers

  • Default to area=no (except for multipolygons).
  • Define natural=cliff on areas (i.e. on multipolygons or with explicit area=yes) as a deprecated synonym for natural=bare_rock.
  • Define natural=cliff on nodes to mean rock spires, which may alternatively be micro-mapped as a surrounding, counter-clockwise, linear natural=cliff.
  • Do not deprecate natural=cliff on nodes until a dedicated tag (like natural=spire) is approved.

Reasons

  • Many peaks or rock formations are surrounded by cliffs. Tagging them with area=no every time comes unhandy, and it would often be forgotten.
  • area=* is normally used to turn linear into areal features, not the other way round.

Examples

Mapnik Profile Description
Cliff sample1 render.png Cliff sample1 profile.svg closed-way, counter-clockwise natural=cliff for a steep edge around a mesa or rock
Cliff sample2 render.png Cliff sample2 profile.svg closed-way, clockwise natural=cliff for a steep edge around a polje or sinkhole

Example for a cliff that should be rendered, but currently isn't: way 73815139

Discussion

Please leave your comments on the talk page.

Voting

  • I approve this proposal I approve this proposal. --Fkv (talk) 00:36, 30 December 2014 (UTC)
  • I approve this proposal I approve this proposal. Javbw (talk) 03:07, 30 December 2014 (UTC)
  • I approve this proposal I approve this proposal. --Polarbear w (talk) 10:15, 30 December 2014 (UTC)
  • I approve this proposal I approve this proposal. Math1985 (talk) 10:38, 30 December 2014 (UTC) Thanks for sorting this out.
  • I approve this proposal I approve this proposal. --Sarchittuorg (talk) 11:40, 30 December 2014 (UTC)
  • I approve this proposal I approve this proposal. Janko (talk) 12:07, 30 December 2014 (UTC)
  • I approve this proposal I approve this proposal. Sommerluk (talk) 16:44, 30 December 2014 (UTC) Nice work!
  • I approve this proposal I approve this proposal. --Kaitu (talk) 17:17, 30 December 2014 (UTC) Nice work, it also reminds the need for a natural=spire proposal.
  • I approve this proposal I approve this proposal. -- RicoZ (talk) 21:03, 30 December 2014 (UTC)
  • I approve this proposal I approve this proposal. -- --Hedaja (talk) 12:01, 31 December 2014 (UTC) But I would recommend not using natural=cliff for nodes. As mentioned natural=spire would be the better choice.
  • I approve this proposal I approve this proposal. Warin61 (talk) 22:13, 2 January 2015 (UTC)
  • I approve this proposal I approve this proposal. --Tordanik 13:31, 3 January 2015 (UTC)
  • I approve this proposal I approve this proposal. JB (talk) 09:21, 5 January 2015 (UTC) Good someone took time to write this through
  • I approve this proposal I approve this proposal. TheDutchMan13 (talk) 07:31, 9 January 2015
  • I oppose this proposal I oppose this proposal. natural=cliff on nodes is a bad idea Mateusz Konieczny (talk) 16:55, 10 January 2015 (UTC)

This proposal has been approved with 14:1 votes. Three voters do not like natural=cliff on nodes. Two of them suggest natural=spire instead. Note that this proposal does NOT intruduce natural=cliff on nodes, as this was already introduced in 2006. This proposal just introduces an interpretation. For those who prefer natural=spire, I created a draft Proposed features/natural=spire. Feel free to take over. I am not going to push it myself, because it is essentially a synonym for natural=cliff. I am ok with either. --Fkv (talk) 16:16, 14 January 2015 (UTC)