[GRASS-user] Re: Is it possible to export a Raster to KML

Hamish hamish_b at yahoo.com
Fri Oct 28 16:05:35 EDT 2011

Helmut wrote:
> ...
> > in my experience overlaying kml (vector and raster)
> > with EPSG:4326 in google
> > earth works relatively well in flat areas, in mountain
> > areas there are
> > sometime distortions therefore.
> I can confirm this from my (limited) experience to export
> data to KML. To correct for the geoid heights, you could use
> the previously indicated map and calculate the local
> ellipsoid-geoid difference and vertically shift your vector
> data with v.transform.
> Then export to KML. For raster, use r.mapcalc to shift.

n.b., IIUC raster KML support in google earth is essentially a
hack building on/abusing their raster-icon support.
they may have improved things, but this is what I was lead to
believe at the time of writing r.out.kml.

probably it is useful to consider if the ellipsoid-geoid
difference is important vs. the overall vertical differences
in the data, if the result is just for viewing maybe it is not
worth the trouble.


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