[Tagging] Double, double, toil and trouble (how to map Witch's Cauldron?)

[Paul Allen]

On Sun, Oct 7, 2018 at 11:56 PM Joseph Eisenberg <joseph.eisenberg at gmail.com>
wrote:

> A collapsed cave on land is a sinkhole. Is that not appropriate?
>

The wiki for natural=sinkhole seems to imply it is for any type of
sinkhole, however formed.  But
the wiki for sinkhole=* doesn't have anything that precisely matches this,
although sinkhole=pit
might do.

The natural=cliff idea is also sensible and correct for the edge of the hole
>

In this case, I think so.   I watched a youtube video of somebody walking
along the footpath nearby
and it gave me vertigo. :)

Natural=arch on a node is a great idea for the natural bridge between the
> collapsed section and the open sea. There are plenty of similar features on
> rocky coasts, Eg Oregon, Baja California, and in deserts due to wind
> erosion (eg Natural Arches monument in Utah)
>

It's not widely used and it's not documented, but it's definitely
appropriate.   One of the examples
I found of it on an area also had layer=1 but I have my doubts about that.
The sea is at sea level
and the ground is at ground level, so is it layer 1 or 0?  Probably best
not to bother with layer.

Small collapsed sea caves can become a “blowhole” if wave action causes
> water to erupt up through the hole, but it doesn’t sound like this is the
> case in this particular place.
>

You can fit quite a few kayaks in there and there's a small beach that
could hold a dozen people.  You
might get a water eruption if there were a tsunami.

That still leaves me wondering what to do with the water.  It's been mapped
as natural=water
without specifying what type of water because there's nothing that
matches.  The closest is
water=lagoon, but there's no barrier.  I'm half-inclined to map it as the
sea by tweaking the
coastline: if the natural arch collapsed then it would be mapped as sea.
If the natural arch collapsed
and were replaced by a man-made bridge it would still be sea.

It's complicated. :)

-- 
Paul
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