[fitswcs] WCS documents

[Arnold Rots]

It has one major disadvantage: the definition of the units list -
which I don't think is controversial - may be held up by mixing it
with the square brackets proposal - which I think is controversial.

  - Arnold

William Pence wrote:
> 
> Peter Teuben's suggestion, below, to add more examples to the current
> keyword units proposal highlights the awkwardness of the current situation:
> the convention for enclosing the keyword units in square brackets is being
> defined in one place (proposed to be added to section 5.3 of the FITS
> Standard), but recommendations for the contents of the units string itself
> are defined in another place (Appendix B of WCS Paper I).   I think these
> proposals need to be merged into a common proposal that would replace the 2
> sentences that are currently in the Units section 5.3 in the FITS Standard. 
> Section 5.3 is the logical place to put all units-related information; other
> sections of the Standard which need to deal with units (e.g., the discussion
> of the TUNITSn keyword in sections 8.1.2 and 8.3.2) simply refer back to
> section 5.3.  I think it is a bit inappropriate to have the discussion of
> the allowed units strings only in the WCS paper, because this is relevant in
> many other contexts that have nothing to do with WCS.
> 
> So, I propose the following:  We remove appendix B from the WCS paper, merge
> it with the current keyword units proposal at
> http://heasarc.gsfc.nasa.gov/docs/heasarc/fits/keywordunits.html, and submit
> this as a separate proposal to replace the current section 5.3 in the FITS
> Standard. 
> 
> This has a number of advantages:
> 
> 1.  It simplifies the WCS paper.  All the WCS paper needs to state is:
> "Units must follow the prescriptions of section 5.3 of the FITS Standard". 
> This will also remove any debate about the allowed units strings when the
> WCS papers come up for a vote.  I believe Appendix B could be removed from
> Paper I with little or no change to the rest of the paper and thus should
> not introduce any additional delay in getting the WCS Papers approved.  I
> may have missed it, but I didn't see any reference to Appendix B in the body
> of the paper.  
> 
> 2.  This new Units proposal can be prepared and submitted to the FITS
> committees very quickly.  Someone just needs to merge the text from the 2
> separate proposals, and perhaps make a few editorial changes to make the
> language suitable for inclusion in the FITS Standard.  Eric is probably the
> logical person to do this, but I am certainly willing to help.
> 
> Does anyone else think this is a good idea??
> 
> -Bill
> 
> Peter Teuben wrote:
> > 
> > Bill,
> >   do we have a good link to the IAU Style Manual. I don't even think I have
> > a copy of it, despite that we often talked about it in the NOST document(s).
> > 
> > One thing I was wondering about is the academic possibility that there
> > is a units which requires a lot of characters, so we could run out of space.
> > 
> > It would be good to add one or two more example or more complex variables,
> > e.g. G (gravitational constant) and something with a bit more "math" to
> > show the syntax.
> > 
> > Secondly, what is the requirement if something is dimensionless. Leave it out,
> > or use [] explicitly? THings that just came to mind as I revisited this page.
> > 
> > -peter
> > 
> > On Wed, 10 Oct 2001, William Pence wrote:
> > 
> > > Eric and Mark,
> > >
> > > As a reminder of what was mentioned at the FITS BoF at the ADASS meeting, a
> > > proposal for how to specify the physical units of a keyword value has been
> > > submitted to the chair of the North American FITS committee for
> > > consideration.  The full proposal can be viewed at:
> > >
> > > http://heasarc.gsfc.nasa.gov/docs/heasarc/fits/keywordunits.html.
> > >
> > > It was suggested that Appendix B in your first WCS paper might be revised to
> > > also mention this keyword units convention.
> > >
> > > In fact, once your WCS papers are approved and become part of the FITS
> > > Standard, it might make sense to move most or all of your appendix B into
> > > what is now section 5.3 (the Units section) of the FITS Standard.
> > >
> > > regards,
> > > Bill
> > > --
> > > ____________________________________________________________________
> > > Dr. William Pence                          pence at tetra.gsfc.nasa.gov
> > > NASA/GSFC Code 662         HEASARC         +1-301-286-4599 (voice)
> > > Greenbelt MD 20771                         +1-301-286-1684 (fax)
> > >
> 
> -- 
> ____________________________________________________________________
> Dr. William Pence                          pence at tetra.gsfc.nasa.gov
> NASA/GSFC Code 662         HEASARC         +1-301-286-4599 (voice)     
> Greenbelt MD 20771                         +1-301-286-1684 (fax)
> 

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Arnold H. Rots                                Chandra X-ray Science Center
Smithsonian Astrophysical Observatory                tel:  +1 617 496 7701
60 Garden Street, MS 81                              fax:  +1 617 495 7356
Cambridge, MA 02138                             arots at head-cfa.harvard.edu
USA                                     http://hea-www.harvard.edu/~arots/
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