[FWTools] gdal_merge color and res issue

[Travis Kirstine]

Are both your images single band with a color table?  Gdal_merge
assumes that all images have the same colour table if single band (I
think).  You may have to convert the images to RGB (pct2rgb.py) before
the merge.  Gdal also uses the last images resolution for the output
(world geotiff).  You can set the resolution with the -ps parameter.
You may want to try gdalwarp to do the merge instead and make use of
the different types of resampling

gdalwarp -tr 100 100 -r cubic input1.tif input2.tif output.tif

Regards

2009/2/12 james2009 <gkenny_2000 at yahoo.com>:
>
> Hi all,
>
> I am trying to merge two Geotiff into one. They are a world and US Geotiff
> images. It looks fine on layer overlap in OpenEV tool (us show in right area
> in world background and in color). But when I try to merge them into one
> using gdal_merge.py (FWTools 206 Linux), it become BW and lose lot of res.
> Would you please help me out with this issue?
>
> I am looking for a way to automate this process.
>
> Thanks for the help.
>
> Tom
> --
> View this message in context: http://www.nabble.com/gdal_merge-color-and-res-issue-tp21956550p21956550.html
> Sent from the FWTools mailing list archive at Nabble.com.
>
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-- 
Travis K.

Toronto, Canada
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