Talk:Tag:natural=cliff
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JOSM
JOSM does not seem to know that ways can be tagged natural=cliff. When tagging a way like this, JOSM draws an area nevertheless. --Geogast 08:56, 2 May 2009 (UTC)
two meanings for "cliff"?
- a) "cliff" = material
- b) "cliff" = up/down
Sometimes a "cliff" is a wide flat rock in a flat landscape. Or a small steap coast line. Or a climbing rock. Or a rocky landscape. Or the Swiss Alps. Or a mix of all...
How do we distinguish this all? --Markus 09:45, 31 May 2009 (UTC)
(a) It seems to me that natural=cliff indicates both "material"=stone/rock and "up/down", this is a useful tag. Additionally I propose a tag for a landscape with bare bedrock, as in mountain areas and other eroded places, influenced by IOFmapping i propose natural=bare_rock. /Johan Jönsson 14:15, 27 September 2009 (UTC)
how to draw it anyway
Some thoughts about this tag:
- there are cliffs in both directions, to the left as well as to the right. The tag is not made for this case
- there are cliffs surrounding a flat space or a cliffy area. When using the tag for an area, what does that mean?
- use as a point could be nice to mark climbing gardens. It does not supply a geographic description, as there is no right or left. Mark a mountain's peak as the topmost point if you want.
I'd suggest to use it as a way if it is a crête (french) or Grat (german). So the slopes are on both sides. We could tag it as oneway=yes, meaning the cliff is on the right side. When used as an area, I interpret it as marking an unpassable area, the cliffy sides on the outer edge. I don't know how to use it if it does not mark a closed area. The area use also does not tell me whether there is more cliffy ground on top of the area, i.e. when passing the outer cliff, what comes after? And what about a cliffy area which surrounds a hole or valley? An abandoned quarry, for example.
So, use as an area does not really fit to mark the rock's edge, but marks a cliffy area instead. Marking the cliff in itself needs a nonclosed way w/cliff=yes. --Thomas 07:35, 09 June 2009 (UTC)
Cliff areas
How should Mapnik render cliff polygons? Where a cliff is at a moderate slope, for example along Devon's Jurassic Coast where it's crumbly sandstone, the cliff occupies a section of land. Commonly this is a thick variable area between a clifftop way and a beach or coastline at the bottom.
Marking a cliff way at the top is OK for marking the edge of a vertical (Dover-style) cliff but it would be good to render these cliff polygons in some way. Rendering the enclosing way is incorrect: that suggests a crater lip. Andygates
- There are some proposals, that it would be better to separate steep areas and solid rock faces, but none has gained any further support: natural=bedrock (or similar) for the visible rock face and natural=cliff separately along the highest edge of the steep area. Even then it's a bit incomplete description, but better than a crater or table outline. Alv 11:48, 25 October 2009 (UTC)
- That's pretty good: it lets the cliff way define the dangerous lip edge, and fills in the otherwise unmapped area. Andygates
Slope
Hi. I've been trying to tag the edge of a Motte (specifically Bedford Castle), and came to the conclusion that this tag was the nearest thing we have, since it describes a steep slope.
What do people think about using something like slope = 45 degrees in conjunction with the cliff tag for stuff which isn't vertical? Ojw 17:38, 2 August 2009 (UTC)
-- I've been using man_made=embankment for these, when mapping hill fort bank-and-ditch structures. They're definitely not natural. Andygates
Crater Rim
I have put a cliff around the "Meteor Crater" in Arizona here [1]. Maybe a new area key called "crater" would be usefull. It could use the same rendering as cliff in a large scale. Tagging could be like: natural=crater, crater=meteor/volcanic or even caldera=major/minor with the main caldera rendered in more scales than all only showing up in close viewing. On a second thought maybe crater should only include meteor/volcanic(including maar?) with slopes on the inside while caldera should go to volcano with slopes on both sides. --T.woelk 09:14, 26 September 2009 (UTC)
Cliff requirements
When is a cliff a cliff and when is it just a slope or a "crease" in the landscape? I suggest at least one elementary requirement:
- You should not be able to ascend it without using your hands (unless there is also a path crossing the cliff).
When natural=cliff is part of natural=coastline
How is this solved? Draw a cliff parallel to the coast? Relation? Skippern 19:00, 1 July 2011 (BST) In this case we shouldn't use values like "natural=coastline;cliff" because rendering could produce an "overflowing" see. It is better to produce a new way.If the cliff is absolutely vertical, this cliff-way can use the nods of the coastline, but normaly cliffs are more or less inland.--Hurdygurdyman 08:51, 14 October 2011 (BST)
