On 08/09/2017 09:54, Colin Smale wrote:
Does anyone have any idea whether the elevations, be they in feet or
metres, are all respecting the wiki definition of being the height
above MSL according to EGM96 (not sure what that would mean in
landlocked areas) and NOT WGS84 or (strictly speaking) relative to
local MSL?
Not without checking the provenance of the data in OSM, no. At least in
the UK, peak ele values will have come from a variety of sources:
o "Well known values" that "the height of mountain X is Y"
o Some value copied from some other (hopefully out of copyright) map
o A value read from a GPS or phone. With a bit of luck that person
might have calibrated the barometer in that device recently, but there's
no guarantee. A non-barometric GPS-only derived elevation is likely to
be even worse.
In the UK where I am, there are a significant number of peaks added by
one mapper based on spot heights from old OS maps - many of these are
not actually peaks at all, and many aren't in the correct place.
Best Regards,
Andy
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