[SpectralDM] - UTypes changes

[Laurino, Omar]

Hi All,


>
> I really don't see any reason for an intermediate SpectralDM 2.0 at
> this point. If ImageDM is to be based upon ObsCore, then SDM 2.0 should
> be as well, and we will have a consistent set of modern data models.
>
>
I tend to agree with Doug on this. Mark is making a huge effort to put
everything together in a consistent, robust, future-proof framework. If we
can afford to delay Spectral2.0 and make sure it is in sync with the rest
of the framework, I would go for it.

I believe this should be discussed at the TCG level (and between Jesus and
myself before that, I guess), though.


It is not necessary to move Char2 to Rec status to do this.  All we
> need to do are make the minor changes to ObsTap/ObsCore as some of
> us proposed last fall.  We already defined the slight modifications
> to the Utypes at that time.
>

I disagree with this. During the discussion whether or not we should have
reopened ObsCore to make the suggested changes, it was stated that ObsCore
*is not* a data model, but a view on an unspecified data model. As such, it
is part of the specification of a DAL interface, which is fine.

Part of Mark's effort is to make sure that we also have at least a basic
ObservationDM for the benefit of Cubes, Spectra, and SEDs, because we
indeed want to have all DMs to be modern, interoperable, and to derive them
from a common set of core models.

So, I would keep the good separation of concerns between DAL interfaces and
Data Models, and let Mark keep up the unbelievable work he is doing without
introducing flaws in the framework without good reason.

As for the prototypes, that's what they are: prototypes, and we know that
they are subject to change. We must consider that Mark's work is also meant
to overcome severe issues we had with the implementation of production
applications (those date 3 years back in time as well), but nevertheless we
should make sure that people's prototypes are not going to be disrupted, so
any feedback on precisely how the current drafts impact the prototypes is
valuable.

Thanks,

Omar.




>
> On Sat, 3 May 2014, CresitelloDittmar, Mark wrote:
>
>  On Fri, May 2, 2014 at 5:45 PM, Douglas Tody <dtody at nrao.edu> wrote:
>>
>>  So for example, in the latest (and earlier) SDM draft we have:
>>>
>>>     Char.SpatialAxis.Coverage.Location.Value
>>>
>>> Whereas in ObsCore and the ImageDM (and Char2) as of last fall:
>>>
>>>     Char.SpatialAxis.Coverage.Location.Coord.Position2D.Value2.C1
>>>
>>
>>    Char.SpatialAxis.Coverage.Location.Coord.Position2D.Value2.C2
>>
>>>
>>>
>>
>> Ah.. Those are Char utypes, and the Spectral model has a simplified Char
>> model as per the original requirements.
>> You're suggesting that this revision should remove the simplifications and
>> reference the complete model. BTW, that would have to be Char-1.13 since
>> Char2 is not a recommendation.  Either way, Char uses STC Coordinates for
>> these.
>>
>> For this update of the 2013 Spectral working draft,  the goal was to keep
>> the footprint fairly small.. making the Dataset level changes which were
>> pretty stable at that time.  We wanted to allow this doc (which has been
>> sitting idle) to move forward, as there are people anxious to use it.
>>
>> Once the Cube work progressed further, and the Data sections became more
>> stable, another update would be needed, to bring it in line.
>>
>>
>>
>>
>>> Others differ as well, although I have not done a careful inventory.
>>>
>>> I have not followed all the discussions, but as this has nothing to do
>>> with Dataset, and is inconsistent with ObsCore/ObsTAP, I suspect there
>>> is an inconsistency.
>>>
>>>         - Doug
>>>
>>>
>>


-- 
Omar Laurino
Smithsonian Astrophysical Observatory
Harvard-Smithsonian Center for Astrophysics
100 Acorn Park Dr. R-377 MS-81
02140 Cambridge, MA
(617) 495-7227
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.ivoa.net/pipermail/dm/attachments/20140504/f4f22e57/attachment.html>