[fitsbits] Re: Fits format for RGB-images

[Patrick Chevalley]

Hi Juergen,

Your second proposition is the right one 
(NAXIS3  =                    3 / Number of Colors)

NOST FITS standard specify :
Arrays of more than one dimension shall consist of a sequence such
that the index along axis 1 varies most rapidly,that along axis 2 next
most rapidly, and those along subsequent axes progressively less
rapidly, with that along axis m, where m is the value of NAXIS,
varying least rapidly;

Colors plane for a RGB image can be assimilate to frequency  in a
multispectral image. 
Use CTYPE3 = RGB to identify this file.

You can find an example on the FITS test "tape" 
The mandrill RGB image :
http://www.cv.nrao.edu/fits/data/tests/ftt4b/file006.fits
some comment on this file:
http://www.cv.nrao.edu/fits/data/tests/ftt4b/ftt4.ps

Patrick Chevalley