[Talk-us-massachusetts] Craters in MA, Starting a discussion

[Alan & Ruth Bragg]

mtc raises an interesting question (see below).
In eastern MA there were over 1000 imported cliffs (COASTAL BANK BLUFF OR
SEA CLIFF) that were closed ways tagged as natural=cliff.  That
representation doesn't hold up in OSM and looks like a hole or a volcano
crater.

What I've been doing is splitting the "cliff" way at the base of the cliff
and creating a multipolygon from the two pieces. I remove the "cliff" tag
from the bottom section and tag the polygon area as natural=scrub, scree or
sand.
This represents (to me at least) a coastal cliff with a top and a bottom
and a face or slope.

There's an example at
http://www.openstreetmap.org/way/82328595#map=17/41.68986/-69.95034

There's a ton of discussion about cliffs at
http://wiki.openstreetmap.org/wiki/Talk:Tag:natural%3Dcliff

I'm not too worried about the OSM definition of a cliff being a near
vertical drop.

Alan

Here's the message I received from mtc

​
Dear Alan, I am taking a OSM mapping holiday! I am visiting Cape Cod for
the first time, with the intention of surveying and updating OSM. It is a
great way of exploring this area. I see you have updated some of the
beaches near here. Perhaps you could consider this problem that I have
seen. One of the imports placed natural=cliff on several of the coastal
beaches. The OSM wiki defines a cliff as a near-vertical drop, which is not
true for these sandy beaches. I removed one such import at the Chatham
Lighthouse, which was especially unsettling since it was a closed-area: as
if all the cliffs circled a deep hole. In my opinion all those cliffs
should be removed. I saw very few high points on my drives down this lovely
landscape. What do you think? You must struggle with all the MASS-GIS
imports that happen here!
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