[gdal-dev] Re: preserving alpha channel data with gdal_polygonize.py

[Chaitanya kumar CH]

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 <thakkar at 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.
>
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-- 
Best regards,
Chaitanya kumar CH.

+91-9494447584
17.2416N 80.1426E
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