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<p>Hi all,</p>
<p>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.</p>
<p>But like Markus, many of my co-authors convinced me that less
attributes will be more error-free.</p>
<p>I was still uneasy with the MJD/JD being hidden to the VOTable
human reader!</p>
<p>So I I would like to support Mark Taylor's proposal with one
little change</p>
<p>I find It's strange that timeorigin contains the time
representation.</p>
<p>So I suggest timeorigin="MJD-origin" or "JD-origin"</p>
<p>Cheers</p>
<p>François<br>
</p>
<br>
<div class="moz-cite-prefix">Le 28/11/2018 à 12:18, Mark Taylor a
écrit :<br>
</div>
<blockquote type="cite"
cite="mid:alpine.LRH.2.21.1811281116001.4052@andromeda.star.bris.ac.uk">
<pre wrap="">On Wed, 28 Nov 2018, Markus Demleitner wrote:
</pre>
<blockquote type="cite">
<blockquote type="cite">
<pre wrap="">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.
</pre>
</blockquote>
<pre wrap="">Hm, I see. The trouble is that I don't think we can write
</pre>
<blockquote type="cite">
<pre wrap=""> [...]
which MUST be present when the time value being annotated represents
an interval elapsed from an origin, such as MJD.
</pre>
</blockquote>
<pre wrap="">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: <a class="moz-txt-link-freetext" href="http://docs.g-vo.org/timesysnote.pdf">http://docs.g-vo.org/timesysnote.pdf</a>, p. 4
bottom; this doesn't have any language on the aliases yet)?
</pre>
</blockquote>
<pre wrap="">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
<a class="moz-txt-link-abbreviated" href="mailto:m.b.taylor@bris.ac.uk">m.b.taylor@bris.ac.uk</a> +44-117-9288776 <a class="moz-txt-link-freetext" href="http://www.star.bris.ac.uk/%7Embt/">http://www.star.bris.ac.uk/~mbt/</a>
</pre>
</blockquote>
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