[Freegis-list] Newbie Question

[Frank Warmerdam]

Nico de Haen wrote:
> This calculator gives only the geoid height, not the height of the 
> surface above sea level.
> (For Mount Helen,  46°11'49.01"N, 122°10'35.45"W it shows 4.15 m...)

Nico,

There are WCS servers providing elevation data for the world that you could
query.  I run an SRTM30 server, but that is pretty coarse data.  What
degree of spatial precision were you needing?

   http://maps.gdal.org/

WCS can be queried from from PHP, but the return result (at least of my
server) is a raster file which might be hard for you to extract the value
from.  In theory I could enable "WMS getfeatureinfo" style query from the
raster data on the corrsponding WMS service and then you would get a small
GML document.  But I'm not sure how hard that would be to get working.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Programmer for Rent