[Proj] Problem overlaying georeferenced images in Google,
support.mn at elisanet.fi
support.mn at elisanet.fi
Sat May 31 04:20:11 EDT 2008
are you sure the "gdalwarp" you are using uses the latest proj-4 libraries?
Are you sure all programs are doing what thye should? If so, it is maybe the
input data (assumptions) then?
Jorge <jorge.arevalo at gmail.com> kirjoitti:
> Now, the results in Google Earth:
> The image before reproyecting (UTM zone 30 datum ED50)
> The image reproyected
> What's the problem?:
> - The input image's projection really isn't UTM ED50 (Mapinfo lies??), or is bad georeferenced (low probability...)
> - The output image's projection really isn't GMaps projection (assuming GMaps projection = GEarth projection)
> - GMaps projection not equal GEarth projection (I think so...)
> - Any other?
> The line executed:
> -s_srs "+init=epsg:23030 +towgs84=-84,-107,-120,0,0,0,0"
> -t_srs "+init=epsg:3785 +towgs84=0,0,0,0,0,0,0"
> -tr 250 250
> -co INTERLEAVE=PIXEL
> The epsg codes:
> Input code (23030):
> # ED50 / UTM zone 30N
> <23030> +proj=utm +zone=30 +ellps=intl +units=m +no_defs <>
> Output code (3785):
> # Spherical/Web Mercator
> <3785> +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 <>
> Sorry for the insistence, and thanks a lot
> Jorge wrote:
> > The EPSG code 3785 is a custom one, but the same of 900913 (I didn't know it thanks), except for the "+wktext" term. What does it mean?
> > OK, I'm lost with this issue. Could my calcs be wrong? I have, for example, this image:
> > http://www.nebulared.com/tmp_geo/UTM_ED50_Balearic_Island.png
> > And is georeferenced by this world file:
> > http://www.nebulared.com/tmp_geo/UTM_ED50_Balearic_Island.wld
> > The image is obtained for a MIF/MID couple of files with UTM projection, zone 30, ED50 datum (Mapinfo said... I don't know what
> > are the dX, dY, dZ parameters, buth they must be -84, -107, -120). Really, the raster file obtained from MIF/MID files isn't a
> > PNG file, but I did the transform to "see" what I was doing.
> > OK, I need to reproject the image, and the output image must be used to overlay it in a GMaps' frame. This is my last attempt:
> > gdalwarp
> > -s_srs "+init=epsg:23030 +towgs84=-84,-107,-120,0,0,0,0"
> > -t_srs "+init=epsg:3785 +towgs84=0,0,0,0,0,0,0"
> > -tr 250 250
> > -co INTERLEAVE=PIXEL
> > UTM_ED50_Balearic_Island.png
> > GMaps_Balearic_Island.tif
> > Then, I transform the TIFF file in a PNG (transformation OK) and I have this image:
> > http://www.nebulared.com/tmp_geo/GMaps_Balearic_Island.png
> > But the image doesn't fit exactly in the map... Is there any error in this reprojection? If the projection is OK, I need to review
> > the rest of the code...
> Proj mailing list
> Proj at lists.maptools.org
More information about the Proj