[Proj] Problem overlaying georeferenced images in Google, Maps(projection problem!)

Jorge jorge.arevalo at gmail.com
Thu May 29 12:18:27 EDT 2008

Hi Eric

Mmm... just now I was reading about datum convert and +towgs84. But the GMaps datum is somehow different from WGS84, is'n it? Can I use +towgs84 instead of this?

Thank you!


> > gdalwarp
> >     -s_srs "+proj=utm +zone=31 +ellps=intl +units=m +no_defs"
> >     -t_srs "+proj=merc +lat_ts=0.0 +lon_0=0.0 +k=1.0 +x_0=0.0 +y_0=0.0 
> > +a=6378137.0 +b=6378137.0 +units=m +nadgrids=@null +no_defs"
> >     <raster file name> <reprojected raster file name>
> > 
> > Then, I did the reprojection, but I still have the problem... better 
> > look, but still remains... Bad overlaid images
> > 
> > I think that the proj.4 parameters are correct. ...
> [snip]

> It looks like you are missing the datum transformation parameters to convert from ED50 to WGS84.  You need to add the +towgs84 
> parameter to your source projection.  However, I can't help you with suggested values for that parameter for your source 
> coordinate system.  You'll have to do some research.
 > -- > > Eric G. Miller > Staff Programmer > CA Dept. of Fish & Game

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