more on FITS and VO

[Guy Rixon]

This change sounds unhelpful.  Something with NAXIS=0 isn't an image; you
can't display it in an image viewer.  Surely the point of image/fits is to
separate those datasets that can be passed to a generic image-viewer from
those where the receiving programme needs to know the semantics of the data?

On Wed, 26 Nov 2003, Robert Hanisch wrote:

> I've been asked to poll the VO community concerning the proposed FITS MIME
> type and a restriction that has been suggested:
>
> > Do you, or other members of the VO community, have any objections to this
> > change to the FITSMIME proposal?  The effect of this one word change (from
> > 'must' to 'should') would be to allow null images (with one or more NAXISn
> > keywords = 0) to be given the mime type "image/fits".  Without this change
> > in wording this would not be allowed, and such null images would have to
> be
> > given the mimetype "application/fits".  This appears to be the last
> question
> > to be resolved before the FITS committees can vote on the proposal (very
> > soon I hope).
> >
> > Bill (Pence)
> >
> > -------- Original Message --------
> > Subject: Re: MUST or SHOULD?
> > Date: Tue, 25 Nov 2003 11:31:53 -0800
> > From: Steve Allen <sla at ucolick.org>
> > To: William Pence <William.D.Pence at nasa.gov>
> > CC: Steve Allen <sla at ucolick.org>, "Wells, Don" <dwells at NRAO.EDU>
> > References: <3DF674E3.9FEFF3B8 at nasa.gov>
> > <Pine.OSF.4.30.0212111815150.1365-100000 at poseidon.mi.iasf.cnr.it>
> > <20021211194531.GA7781 at ucolick.org> <3FC3A87D.4333CA1F at nasa.gov>
> >
> > On Tue 2003-11-25T14:07:41 -0500, William Pence hath writ:
> > > I understood from the FITSBITS discussion in June 2003 that you were
> going
> > > to modify:
> > >
> > >     A FITS file described with the media type "image/fits" MUST have a
> > >     primary header and data unit (PHDU) which consists of at least one
> > >     pixel.
> > >
> > > so that instead of "MUST" it would read "SHOULD".
> > >
> > > Your current draft of the proposal at
> > > http://www.ucolick.org/~sla/fits/mime/rfcFITS.txt
> > > still says "MUST"
> > >
> > > Is that correct?
> >
> > I have not changed it pending a clearer view of the situation.
> >
> > I have asked Bob Hanisch to inquire deep into the VO community in
> > hopes of learning whether there seems to be justification for
> > zero-pixel instances of image/fits.  I have not been able to elicit a
> > definitive confirmation of the need.
> >
> > The principal objector to SHOULD was Tim Pearson, but Tim seemed
> > to think that these MIME types should be more prescriptive than
> > I believe is possible given the pre-existing level of anarchy.
> >
> > --
> > Steve Allen          UCO/Lick Observatory       Santa Cruz, CA 95064
> > sla at ucolick.org      Voice: +1 831 459 3046
> http://www.ucolick.org/~sla
> > PGP: 1024/E46978C5   F6 78 D1 10 62 94 8F 2E    49 89 0E FE 26 B4 14 93
> >
>

Guy Rixon 				        gtr at ast.cam.ac.uk
Institute of Astronomy   	                Tel: +44-1223-337542
Madingley Road, Cambridge, UK, CB3 0HA		Fax: +44-1223-337523