[gdal-dev] nodata - mask question

[Travis Kirstine]

I have a general question regarding how to handle the null values with
1 band byte grey scale images.  Typically I will receive a image with
pixels at the edges of a image with a  value of 0 however some of the
interior pixel values (shadow areas) share the same pixel value.  My
old approach was just to ignore the interior values and run gdalwarp
indicating the source and target nodata as 0.

Is there a method currently available to distinguish between valid and
invalid nodata values when they both share the same pixel value?



-- 
Travis K.

Toronto, Canada
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"She knows there's no success like failure
and that failure's no success at all."
-Bob Dylan-
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