[Tagging] Elevation and height on vertical features
miketho16 at gmail.com
Fri Jan 8 18:04:52 UTC 2016
On Fri, Jan 8, 2016 at 10:54 AM, Greg Troxel <gdt at ir.bbn.com> wrote:
> Mike Thompson <miketho16 at gmail.com> writes:
> > On Fri, Jan 8, 2016 at 9:47 AM, Colin Smale <colin.smale at xs4all.nl>
> >> How did all the elevation data get into OSM in the first place?
> > The elevations of peaks in the US came from the GNIS import. In turn the
> > GNIS elevations came from the National Elevation Dataset (NED) , and
> > mostly uses the North American Vertical Datum of 1988 . The other
> > problem is that these are not "spot elevations" and therefore the
> > of a peak in the GNIS does not - in most cases - match the official
> > elevation (the ones shown on the old USGS Topo maps and published by the
> > National Geodetic Survey).
> >  http://nationalmap.gov/elevation.html
> >  http://www.usgs.gov/faq/categories/9865/4921
> >  http://www.ngs.noaa.gov/datasheets/
> Perhaps it would be a good project, perhaps via maproulette, to spiff
> this up.
> It can be tricky, though, because the benchmarks on mountains
> are not always the exact summit --
I have wondered about that myself. In addition there are often several
markers near the summit. However, for the few summits that I have checked,
at least one benchmarks has an elevation that matches the height on the
USGS topo map.
> But I get it that the USGS surely publishes mountain heights
I have asked, and so far I have not gotten an answer as to where I can find
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