[Tagging] tagging of "ele" / elevation data e.g. in the context of towers

[Martin Koppenhoefer]

On the German ML we are currently discussing how to applicate "ele" to
towers (and similar situations). There is consensus that the key
"height" is describing the height of the structure from the ground to
the top. There is also consensus to tag elevation data in WGS84 (so
that numbers in local systems would typically have to be converted
before you can enter them).

There are 2 alternatives:

a) ele is the elevation of the ground around/below the tower (in the
case of a mountain summit it would be the elevation of the mountain,
not the tower).

b) ele is the elevation of the highest point at the tagged spot, i.e.
the top of the tower


Comments welcome. The idea is to clarify this aspect on the wiki page
for the key "ele".

cheers,
Martin