Timesys note review

[François Bonnarel]

Hi all,

I think that time representation is MUCH MORE than serialisation (it 
implies a time origin and sometimes a time scale, eg for julian and 
besslian years), so I was initially supporting something close to what 
Arnold's proposed.

But like Markus, many of my co-authors convinced me that less attributes 
will be more error-free.

I was still uneasy with the MJD/JD being hidden to the  VOTable human 
reader!

So I I would like to support Mark Taylor's proposal with one little change

I find It's  strange that  timeorigin contains the time representation.

So I suggest timeorigin="MJD-origin" or "JD-origin"

Cheers

François


Le 28/11/2018 à 12:18, Mark Taylor a écrit :
> On Wed, 28 Nov 2018, Markus Demleitner wrote:
>
>>> Somewhat related: I think the discussion of the timeorigin attribute
>>> in section 2 should be tightened up a little bit, so it's clear that
>>> a value MUST be present for non-year-like time values as well as
>>> saying that it MUST NOT be present for calendar-year-like values.
>> Hm, I see.  The trouble is that I don't think we can write
>>
>>>     [...]
>>>     which MUST be present when the time value being annotated represents
>>>     an interval elapsed from an origin, such as MJD.
>> You see, any time specification represents an "interval elapsed from
>> an origin", be it the Christian epoch, the mythical foundation of
>> Rome, the Hijra, the launch of a space probe or (since I belong to
>> the Church of Unix, my favourite) 1970-01-01T00.00:00Z.  So, I don't
>> think this language works.  But I see the requirement level needs to
>> be made clearer.
>>
>> What about (svn rev. 5245):
>>    
>>    The timeorigin attribute MUST be given unless the time's representation
>>    contains a year of a calendar era, in which case it MUST NOT be present.
>>
>> (to see it in context:http://docs.g-vo.org/timesysnote.pdf, p. 4
>> bottom; this doesn't have any language on the aliases yet)?
> Yes, that's fine by me.  I wasn't that happy with the language
> I suggested either.
>
> --
> Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
> m.b.taylor at bris.ac.uk  +44-117-9288776http://www.star.bris.ac.uk/~mbt/

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.ivoa.net/pipermail/apps/attachments/20181129/59d7bff3/attachment.html>