Fwd: Re[4]: [gdal-dev] gdalwarp: mercator to lambert azimutal equeal area

jumpjack jumpjack at libero.it
Tue Feb 10 14:52:11 EST 2009

I tried georeferencing one of these images ( http://www.oera.net/How2/TextureMaps2.htm ) using MapWindow GIS; the pogram generated a .jgw file, which then I fixed by replacing "," by "." and changing something like 179.12345 to 180.0 .
Then I tried again this command:
>gdalwarp -s_srs  "+proj=merc" -t_srs "+proj=laea" world.jpg  dest.jpg

Ok, program now does not complain for any error... but what I get as output is EXACTLY the SAME image!!!

What's wrong now?
And how do I specify the center of the Lambert projection to be on north pole?

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On 09/02/2009 at 13.47 jumpjack <jumpjack at libero.it> wrote:

From: jumpjack <jumpjack at libero.it>
To: "Wendy Fay Stevenson" <stevensw at erau.edu>
CC: gdal-dev at lists.osgeo.org
Date: Tue, 10 Feb 2009 18:48:45 +0100 
Subject: Re[4]: [gdal-dev] gdalwarp: mercator to lambert azimutal  equeal area

>Thanks, but I can't yet understand...
>I have a map of the whole world. It is 640 pixel wide. "Planar world" is
>44.000.000 meters wide.... so which number should I specify as "A"??
>The same applies for "E".
>About C and F: which coordinates should I specify? Lat and Lon?  This
>would be 90,-180, I guess, being the map centered on Lat,Lon=0,0 and 360°
>wide and 180° tall.
>Thanks for your pacience.
>(Please reply on the list, others could be interested!)
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>On 09/02/2009 at 13.47 Wendy Fay Stevenson wrote:
>>As long as the world file is the same name as the input file to gdalwarp,
>>it will work.
>>As for specifying the world file:
>>A: number of meters across / number of pixels across
>>D & B: 0
>>E: -1 * number of meters in length / number of pixels in length 
>>C and F specify the center of the top left pixel in eastings and
>>northings, i.e. where on the projection the first pixel corresponds to.

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