[gdal-dev] Problem using gdalwarp to reproject Lambert Conformal Conic (LCC) to longlat

[James Hiebert]

Thanks for the quick response.  It was definitely the missing +b.  It seems
that proj will fill in the +b with the same value if +a is given.  Adding +b
to the s_srs flag did the trick.

~James

On Fri, Jan 07, 2011 at 04:51:05PM -0500, Frank Warmerdam wrote:
> On 11-01-07 04:18 PM, James Hiebert wrote:
> > All,
> >
> > Below is a question/probelm from one of my co-workers (who doesn't (yet)
> > want to subscribe to the list).
> >
> > ~James Hiebert
> >
> >
> > From: Hailey Eckstrand<haileye at uvic.ca>
> > Date: Fri, 7 Jan 2011 13:05:10 -0800
> >
> > Hello all,
> > I am trying to reproject a geotif using gdalwarp:
> > gdalwarp -t_srs "+proj=longlat" -s_srs "+proj=lcc +lat_0=47.5 +lat_1=30.0 +y_0=3200000.0 +lat_2=60.0 +x_0=3825000.0 +lon_0=-97.0 +a=6370000" -r bilinear -srcnodata "1e20" -dstnodata "1e20" -tr 0.5 0.5 -te -137.812943839532 33.8985446218588 -102.312943839532 63.3985446218588 mm5i-lcc.tif  mm5i-latlong.tif
> >
> > ERROR 1: Translating source or target SRS failed:
> > +proj=lcc +lat_0=47.5 +lat_1=30.0 +y_0=3200000.0 +lat_2=60.0 +x_0=3825000.0 +lon_0=-97.0 +a=6370000
> >
> > When I use the proj/invproj unix command, it works fine:
> >
> > invproj +proj=lcc +lat_0=47.5 +lat_1=30.0 +y_0=3200000.0 +lat_2=60.0 +x_0=3825000.0 +lon_0=-97.0 +a=6370000<<  EOF
> 
> James,
> 
> I would suggest you collegue be more explicit about the earth models.
> PROJ.4 definitions passed to GDAL utility are parsed by GDAL, converted
> to WKT, and then later converted back to PROJ.4 format and so not all
> definitions supported by PROJ.4 are necessarily supported by GDAL.
> 
> In this case I suspect GDAL is confused by the lack of a +b value for
> the lcc projection.  It may also not handle a missing earth model on the
> geographic coordinate system well.
> 
> Best regards,
> -- 
> ---------------------------------------+--------------------------------------
> I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | Geospatial Programmer for Rent
> 
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-- 
James Hiebert
Lead, Computational Support
Pacific Climate Impacts Consortium
http://www.pacificclimate.org
C178 Segdewick Building, University of Victoria
PO Box 1700 Sta CSC, Victoria, BC V8V 2Y2
E-mail: hiebert at uvic.ca
Tel: (250) 472-4521
Fax: (250) 472-4830