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<font size=3>You can also use the GeoExpress 5.0 trial download from
LizardTech
(<a href="http://www.lizardtech.com/" eudora="autourl">
www.lizardtech.com</a>) that allows you to mosaic and reproject .sid
images in one step. The trial download allows you to work with
images that already are in .sid format without problems. That way
you don't need to go from MrSID to GeoTiff and make a large mosaic as a
.sid image.<br><br>
Best regards,<br><br>
Reinaldo<br><br>
At 09:06 PM 1/24/2006, Frank Warmerdam wrote:<br>
<blockquote type=cite class=cite cite="">On 1/24/06, Dolloff, Matthew D.
(JSC-ER7) <matthew.d.dolloff@nasa.gov> wrote:<br>
><br>
><br>
><br>
> Hello. I am trying to convert some MrSID images into Geotiffs
and tiling<br>
> them together. The MrSIDs are in state plane coordinate system
and I need<br>
> them in WGS84. So I convert the MrSIDs to geotiffs using
mrsiddecode from<br>
> lizard tech. Then I use gdal warp to change the projection
type. Then use<br>
> gdal_merge to merge them together. The problem is that I end
up with a<br>
> black collar when I warp the images and then when I merge them the
images<br>
> cover each other up. Is there anyway, that I can crop those
collars out?<br>
> Here is the link where I am getting the sids<br>
>
<a href="http://www.nysgis.state.ny.us/gateway/mg/2001/suffolk/01ic_t_babylon_l06col.htm" eudora="autourl">
http://www.nysgis.state.ny.us/gateway/mg/2001/suffolk/01ic_t_babylon_l06col.htm</a>
<br><br>
Matt,<br><br>
A couple of approaches would be:<br><br>
o Use gdal_merge to merge the TIFFs before<br>
reprojecting them. Then gdalwarp the
resulting<br>
mosaic.<br><br>
o Or create a big WGS84 mosaic file and gdalwarp<br>
each non-WGS84 file into that, mosaicing at the<br>
same time as reprojecting.<br><br>
In the future gdalwarp will support multiple input<br>
files, essentially replacing gdal_merge for many<br>
purposes. This is already in CVS if you were building<br>
from source. Another option would be to generate a<br>
nodata value or better yet an alpha channel in the files<br>
output by gdalwarp to keep track of the nodata pixels.<br><br>
My suggestion would be the top most option, mosaic<br>
then reproject. Keep in mind that GeoTIFF only<br>
supports file sizes up to 4GB. So if your mosaic is<br>
going to be large, you may need to do it in a format<br>
like Erdas Imagine.<br><br>
Best regards,<br>
--<br>
---------------------------------------+--------------------------------------<br>
I set the clouds in motion - turn up | Frank Warmerdam,
warmerdam@pobox.com<br>
light and sound - activate the windows |
<a href="http://pobox.com/~warmerdam" eudora="autourl">
http://pobox.com/~warmerdam</a><br>
and watch the world go round - Rush | Geospatial
Programmer for Rent<br><br>
_______________________________________________<br>
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Gdal-dev@lists.maptools.org<br>
<a href="http://lists.maptools.org/mailman/listinfo/gdal-dev" eudora="autourl">
http://lists.maptools.org/mailman/listinfo/gdal-dev</a> </blockquote>
<x-sigsep><p></x-sigsep>
Reinaldo Escada Chohfi, Ph.D.<br>
Diretor <br>
GeoDesign Internacional<br><br>
<u><a href="http://www.geodesign.com.br/" eudora="autourl">
www.geodesign.com.br<br><br>
</a></u>E-mail: rec@geodesign.com.br<br><br>
Tel./Fax: 0-XX-12-3153-5115 (Local)<br>
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