On 26/04/19 11:48, Joseph Eisenberg wrote:
I have created 2 proposal pages for natural=mesa and natural=butte
A mesa is defined as "A flat-topped elevated landform surrounded by
cliffs". A mesa may also be known as a table or tableland, potrero or
tepui. See http://en.wikipedia.org/wiki/en:mesa
A butte is defined as "a hill with a flat top surrounded by cliffs."
The width of the flat top is less than the relative height of the
hill. See http://en.wikipedia.org/wiki/en:butte
So in contrast with a natural=butte, in a natural=mesa the width of
the flat area is greater than its height above the surrounding
terrain.
I believe both of these features may be mapped as a node or as an area
with a closed way.
In contrast two these 2 features which are surrounded by cliffs or
steep escarpments, the tag natural=plateau (already in use <100 times)
is often used for large features that do not have clear boundaries,
and therefore cannot be verifiably mapped as an area.
I've also made a proposal page to help define natural=plateau, and
suggest that it not be used with relations or areas.
About the values of the tags, "mesa" and "butte"
While one might use "table" or "tableland", these terms are somewhat
ambiguous, and can be used for very large features. In contrast, the
terms "mesa" and "butte" are fairly well defined in English, even
though they are loan words from Spanish and French. There are few of
these features in England, so it's not surprising that new words were
needed.
See:
https://wiki.openstreetmap.org/wiki/Proposed_features/Tag:natural%3Dmesa
need to make it clear in the description how it differs from plateau/butte e.g.
Flat topped area with sudden elevation, wider or longer than it is high
but horizontal dimension less than 1.6 km.
https://wiki.openstreetmap.org/wiki/Proposed_features/Tag:natural%3Dbutte
need to make it clear in the description how it differs from plateau/mesa e.g.
Flat topped area with sudden elevation, higher that width or length
https://wiki.openstreetmap.org/wiki/Proposed_features/Tag:natural%3Dplateau
The smallest horizontal dimension of a plateau could be 1.6 km ( 1 mile). This
would distinguish it from mesa/butte.
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Note definitions are rough and need some more thought than I gave above.
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