[AstroPy] Need Help about Astropy.table.Table.write

[Derek Homeier]

On 31 Jul 2014, at 04:01 pm, Michael Droettboom <mdroe at stsci.edu> wrote:

>>> As with newton or kelvin… But that leads a bit astray from the original problem.
>>> I certainly think capitalisation variants should be tolerated,
>>> 
>> The problem is that capitalization is meaningful in units. mm vs. Mm is an obvious one.
>> 
> 
> Sorry, I meant to add an even more problematic example.  s (seconds) vs. S (Siemens) is another good one.  wcslib provides flags to convert 'S' to 's' (since that's the more common usage), but that's just a mess.  I *really* would prefer that files just said what they mean.  We're in a growing pain period here, where many legacy FITS files have never used the units in a meaningful way before -- we're never going to get to a place where they are useful for calculation if we aren't strict about their specific meanings.

Completely agree for the case of abbreviations and prefixes. When I wrote ‘should be tolerated’ - 
not ‘accepted’ - I did not want to argue against raising a warning in these cases, and especially not
for writing them to new files at least without a warning. But as you say there is a huge legacy of
FITS files sometimes without any policy on units usage we have to find a strategy to deal with,
one way or the other. ANGSTROM[S] vs. angstrom is certainly one of the least problems here.
I mentioned FORTRAN 6 because I got the impression there are probably lots of users (or software)
that may regard non-capitalised keywords a violation of the standard…

Cheers,
							Derek