[Tagging] Elevation and height on vertical features

Mike Thompson 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>
> wrote:
> >>
> >> 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) [1], and
> it
> > mostly uses the North American Vertical Datum of 1988 [2]. The other
> > problem is that these are not "spot elevations" and therefore the
> elevation
> > 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[3]).
> >
> > [1] http://nationalmap.gov/elevation.html
> > [2] http://www.usgs.gov/faq/categories/9865/4921
> > [3] http://www.ngs.noaa.gov/datasheets/
>
> Perhaps it would be a good project, perhaps via maproulette, to spiff
> this up.

Agree!


> 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
> somehow.
>
I have asked, and so far I have not gotten an answer as to where I can find
the data.
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