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January 2004
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2004.01.23 19:24 "Re: How to convert MINISBLACK to PHOTOMETRIC_RGB", by Frank Warmerdam
Bob Friesenhahn wrote: > On Fri, 23 Jan 2004, Frank Warmerdam wrote: > > > I am by no means an authority on the TIFF specification. My interpretation > > of the file in question is that a sensible application should render the > > first band in greyscale and ignore the 2nd and 3rd since they are extra samples > > with no meaning attached. Without the ExtraSamples tag, I think an application > > should assume the file contains 3 greyscale bands which might be drawn in any > > number of ways. One way would be to draw 1 band, and give the user the ability > > to flip through to see the 2nd and 3rd. Another would be to just treat them > > as RGB (as many multispetral imaging packages will do with the first 3 bands > > of multispectral data). > > > I am no TIFF authority either. I aggree with your summary. The extra > samples could mean almost anything. More than likely the correct > intepretation of the extra samples depends on the vendor extension > tags that libtiff warned about. :-) Bob, Those are GeoTIFF tags. I *know* what the extra samples are, but it isn't clear at all from the tags. Best regards, -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, warmerdam@pobox.com light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Programmer for Rent