On Fri, Jan 8, 2016 at 10:54 AM, Greg Troxel <g...@ir.bbn.com> wrote:
> > Mike Thompson <miketh...@gmail.com> writes: > > > On Fri, Jan 8, 2016 at 9:47 AM, Colin Smale <colin.sm...@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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