wwp@yahoogroups.com:
Re: Google earth elevations accurate?
Erik Krause 2007-Sep-23 18:51:00
On Sunday, September 23, 2007 at 6:29, Caroling Geary wrote:
> Is Google Earth elevation accurate?
>
> I don't have an altimeter, but want to know the elevation of my site.
> Google earth says it is 20 feet. I'm wondering how accurate that is.
> Checking known elevations, so far, it seems pretty good.
As far as I know they use something like a 90m grid and interpolate
values in between. Could be that is better in the US, since for the
US free radar elevation data is available in a smaller grid:
http://edc.usgs.gov/products/elevation.html
If you have a relatively smooth area the values should be accurate.
In the mountains it starts to get difficult, because the resolution
id too low to map rough structures. Summits and spires are usually
too low compared to their real values. At least this is the case for
summits in the european alps, where I collected exact GPS and height
data for most of the important summits (mainly from
http://www.peaklist.org/)
best regards
--
http://www.erik-krause.de