AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

2003.11.16 22:37 "[Tiff] reading Affymetrix tiff images", by sridhar duggireddy
[...]
2004.01.23 15:57 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Bob Friesenhahn
2004.01.23 16:44 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Frank Warmerdam
[...]

2004.01.23 16:44 "Re: [Tiff] How to convert MINISBLACK to PHOTOMETRIC_RGB", by Frank Warmerdam

How does this treat the two extra samples? Does it ignore them?

I believe that GDAL treats the 3 samples as red, green and blue in the command shown by Andrey.

And GraphicsMagick will only extract the primary gray channel.

PS. I don't think the Imagine generated TIFF file is so odd. In the satellite imaging community it is common for us to use MINISBLACK for multispectral tiff files. The only odd part, in my mind, is the use of the unspecified ExtraSamples tag. When I see multi-sample MINISBLACK TIFF files I assume that each sample should be treated as MINISBLACK with no obvious pre-set RGB sample combinations.

Right. MINISBLACK is pretty ordinary. The intent/meaning of the extra samples is undefined and may be proprietary. Perhaps they could be some sort of mask, or overlays which can be enabled/disabled in viewing software.

Bob,

They are not masks. They are just extra MINISBLACK samples/bands/channels. I have worked on the Imagine GeoTIFF code at times, and I don't think the ExtraSamples stuff was meant to imply the extra bands were anything special.

I will agree that including the ExtraSamples <undefined> tag muddies the water quite a bit.

Best regards,

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