On Wed, 23 May 2007, David Berry wrote:
>> Groan. I'm just having flash forwards of moaning astronomers who will
>> always be using either PIXEL or WCS sections and the subtlety of AXIS
>> sections will completely pass them by.
>
> It's nothing to do with AXIS structures - they are simple because they
> always have a one-to-one correspondence with pixel axes - that is,
> 'AXIS' axis N is always associated with pixel axis N. But that's not
> the case with WCS axes. Say you have a spectral cube called fred.sdf
They are the same in most people's minds though :-) Having the WCS axes
permuted from the pixel axes is going to cause havoc regardless.
Carry on though. :-)
> Whilst it will probably do something sensible with a CHANMAP I'm not
> sure it would ever be of any use.
It would only be of use if the pixels that were not part of the section
were masked out. Have you got an example of a 3d WCS for a 2d pixel array
where the sectioning would be useful?
--
Tim Jenness
JAC software
http://www.jach.hawaii.edu/~timj
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