UWS times

[Mark Taylor]

On Thu, 24 Mar 2016, Paul Harrison wrote:

> TOPCAT is a good example of a tool that is designed to work with data
> from both VO and non-VO sources and cannot make the assumption that
> every datetime it sees is UTC - to be able to do meaningful comparisons
> it needs the timezone information.

Umm, as far as I remember[*], I'm afraid it makes exactly that assumption.
In conversions it tolerates a trailing Z, but that's about it.
Although it (sloppily) mentions ISO-8601 in various parts of the
documentation, it will choke on many ISO-8601-compliant time strings,
including ones with trailing [+-]hh:mm modifiers.

I never looked hard at how much effort it would be to treat all
ISO-8601 strings properly (quite likely you can just throw them at
some java class), but I followed the restricted profile allowed
by FITS on the grounds that it's less confusing and satisfies most
people's requirements.  I don't recall anybody ever complaining
about topcat/stilts's failure to work with more general ISO-8601
strings.  So, I'd line up on the "make'em eat UTC and like it"
side of the argument (though preferably without disrupting
existing standards text too much if possible).

Mark

[*] unless someone knows different, in which case please point it out -
    it's always possible that I forgot some parts of the implementation.

--
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b.taylor at bris.ac.uk +44-117-9288776  http://www.star.bris.ac.uk/~mbt/