Draft note on STC in the Registry
Pierre.Fernique at astro.unistra.fr
Mon Jan 29 16:50:04 CET 2018
First of all, thanks Markus for this note
(http://docs.g-vo.org/regstcnote.pdf). On my point of view it is a
pragmatic approach of coverage manipulation challenge which has a good
chance to be implemented and used. I agree for most of the suggestions.
I just highlight these points :
1. *"double precision"* : Our experience on MOCs has shown us that the
coverage is never enough accurate for the users. The approach to
have two levels of precision - a low precision coverage inside
registry, and possibly a high one outside via URL - is certainly a
very good thing.
My question : I imagine that we could have the same need for time
coverage, and may be for energy coverage. See point 5
2. *T**able or catalog coverage ?* Presently, the "FOOTPRINT" element
(cf end of the section 2.2) is dedicated to the global resource. The
problem: for catalogs containing several tables it is actually not
possible to know each individual table coverage. I would suggest
that this IVOA note will propose something to fix this issue.
3. *MOC frame* (related to section 4.1-b) IVOA provides now several
data collection (tables or HiPS) dedicated to planets. In the case
of HiPS, we have had already to introduce new reference coordinate
system as a list of planet names (hips_frame=mercury, venus, moon,
mars, mimas, etc...). This solution works fine for HiPS, but as a
HiPS is distributed with its associated MOC, it means that these
associated MOCs are not celestial, but planet dependent. It could be
a good thing if we use the same controlled vocabulary for HiPS, MOCs
4. *MOC ASCII* => see my previous mail concerning the MOC ASCII
5. *Temporal MOC*. We are starting to explore the idea of a temporal
MOC. In one word - but probably more at the next IVOA meeting - it
would be the same logic of a spatial MOC but for time based, not
HEALPix dependent, but based on a fix reference time system and unit
(JD - barycenter - in fact identical to 2.1 definition). Having a
list of MJD ranges as internal registry coverage will immediately
allow us to build corresponding "TMOC" (and may be later and
extension of the MOCserver also time oriented). So I would applause
the usage of collections of MJD ranges for describing time coverage.
Le 17/01/2018 à 10:58, Markus Demleitner a écrit :
> Dear colleagues,
> Those who attended our session in Shanghai may remember my talk on
> how we can finally get proper STC queries against the Registry --
> I've finally done the various implementation parts to try everything
> out in DaCHS and the relational registry (at this point, it's only on
> the Heidelberg mirror, since harvesting the MOCs is quite a bit of
> Based on that experience, I'd now propose a roadmap for how we could
> move towards more-or-less universal declaration of coverages in
> space, time, and spectrum for the VO Registry. I've drafted
> a Note that I'd like to upload to the document repository -- probably
> some time next week unless you want more time for discussions.
> A draft of the note is available from
> http://docs.g-vo.org/regstcnote.pdf, the sources (that you're welcome
> to work on) are in volute at
> -- this includes a copy of the modified VODataService schema that
> will later be part of the upload.
> After this, I'd be grateful if you (yes, you!) could
> (a) briefly review the thing to and protest quickly if you strongly
> disagree with the main points of the note? Ideally, I'd like the
> note to represent the "rough consensus" that's traditionally half of
> the RFC process (the other part being "running code").
> (b) perhaps look a bit deeper at the stuff if you're interested a bit
> more in the registry/STC borderline. If you still feel comfortable
> with the note then, I'd be happy to include you on the author list.
> I feel a bit odd being the only author on something fairly
> wide-reaching, and certainly some of you out there had important
> roles in shaping what's written there during the past six years or so
> (yeah: according to RegTAP WD-20121112, it removed a first version of
> this...). So: If you can see your name on this note, just drop me a
> note, and don't be shy or overly modest.
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