[GRASS-user] Re: Is it possible to export a Raster to KML
randre at gmail.com
Fri Oct 28 17:06:10 EDT 2011
I find this thread interesting. In my experience overlaying both raster
(orthophoto) and vector data in Google Earth with KML, EPSG:4326 has worked
with no problems whatsoever. So far as I know, GE does not apply a vertical
datum, it simply drapes the 2D data over its internal terrain model.
Would it be possible for you to share some data where you have seen that
this is a problem?
On Fri, Oct 28, 2011 at 1:05 PM, Hamish <hamish_b at yahoo.com> wrote:
> 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.
> grass-user mailing list
> grass-user at lists.osgeo.org
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