[gdal-dev] GDALwarp Mercator to UTMs
geoff at tritonimaginginc.com
Wed Aug 10 14:21:46 EDT 2011
Good day, almost a complete newbie here but making progress!
I have followed all the examples of GDALwarp with some success and also
been able to use GDAL_translate to take an image with no geoferenced
info and generate a UTM GeoTIFF (including screens from Google Earth)
However my ultimate aim is to take a Mercator chart and generate a
background image as a UTM GeoTIFF, this so far has eluded me!
I have a Mercator Chart with the known corners in Lat/Long coordinates
degrees, but I can't find a suitable EPSG/Proj4 projection that allows
the use of Lat/Long degrees to designate -a_ullr for GDAL_translate.
The following almost works:
GDAL_translate -a_srs WGS84 -a_ullr -45 78.5 45 53.5 <source tif> <merc
GDALwarp -t_srs EPSG:32631 <merc geotiff> <UTM geotiff>
But of course the result still has unequally-spaced lines of Latitude
because the WGS84 input to GDAL_translate assumes the "google earth"
type projection...not Mercator
Any ideas are very welcome - I have been circling this problem for
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