[Gdal-dev] Creation of geotiff files with gdalwarp that have a transparent background

[Eric Sokolowsky]

I have been experimenting with the gdal library, specifically the
gdalwarp tool included with the library.  It is very useful, and I have
been able to transform images to a geographic projection.  Is there is a
way to specify a default background color?  Specifically, I wish to
create a geotiff file where the areas not covered by the original source
file are transparent.  Is this possible, or do I need to start hacking
gdal?  Would this change be generally useful to others?

-- 
    ____   __     Eric Sokolowsky    (GST)  NASA Goddard Space Flight Center 
   / __/__/_/__  Visualization Programmer    Scientific Visualization Studio
  / __/ _/ / _/ 301.286.3751                  Mailstop 935.0 Bldg 28 Rm E102
 /___/_//_/__/ eric.sokolowsky at gsfc.nasa.gov   Greenbelt, MD 20771