John, gdal_polygonize script stores the common pixel value in a field for every polygon. By default it is named 'DN', which can be changed by specifying the fieldname option.
You must use the alpha channel to polygonize. So you have to use the -b option to specify that and may have to use the -nomask option too. On Tue, Jul 26, 2011 at 9:21 AM, jt2000 <thak...@nexgenwireless.com> wrote: > Thanks Jay, > > Ideally I would like the data to be in a column of the shapefile output so > I > can load it in the database and use it to query. With gdal_polygonize.py > this doesn't seem possible so I was wondering what other options are out > there. > > -- > View this message in context: > http://osgeo-org.1803224.n2.nabble.com/preserving-alpha-channel-data-with-gdal-transform-py-tp6620877p6620923.html > Sent from the GDAL - Dev mailing list archive at Nabble.com. > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/gdal-dev > -- Best regards, Chaitanya kumar CH. +91-9494447584 17.2416N 80.1426E
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