Datalink

[Petr Skoda]

thanks for explanation - I was thinking about more complex cases than he 
end point of datalink (e.g. animation of datacube)
in this case we had a problem to describe the link of our example pointing 
from individual photometry  point to the original image
We used a SIAPLink with accesURL - as this was  understood by Aladin.

the semantics makes sense and its controlled vocabulary as well..
just I still see philosophical issue with the definition of time

to fit powerspectra frequencies etc ....

so it may be timeseries of (in principle) datacubes - spectra and images 
are degenerated datacubes ...

as an ordered set of entities - eg files in directory havin timestamp


which is diffeent from the time transformation- like
associate the timeseries with its power spectrum

Kepler case e.g.

how to work with this ?


On Sat, 12 Oct 2019, ada nebot wrote:

> Date: Sat, 12 Oct 2019 09:52:07
> From: ada nebot <ada.nebot at astro.unistra.fr>
> To: François Bonnarel <francois.bonnarel at astro.unistra.fr>,
>     Petr Skoda <skoda at sunstel.asu.cas.cz>,
>     Patrick Dowler <pdowler.cadc at gmail.com>
> Cc: Ada Nebot <ada.nebot at astro.unistra.fr>, "<dal at ivoa.net>" <dal at ivoa.net>
> Subject: Re: Datalink
> 
> Hi Pat, Francois, Petr,
>
> Thanks for your comments and responses.
>
> Pat, content_type (the first field I looked into) tells you about the format but not about the actual content. At least this is what I understood.
> This is why I point to the ”semantics" field and adding a vocabulary without having to add an extra column for that.
>
> Francois, Associateddata=timeseries-images,… something like that could work.
>
> Petr, Francois is right in his comment as to what I refer to.
> I thought about the ucd usage of it, perhaps this is something to look into.
>
> I guess the options/questions are:
> 1) add a column for that and add a vocabulary
> 2) use the field semantics and have a controlled
>
> In both cases it points to a vocabulary, and I would vote for 2 in principle since it looks like it would require less effort.
>
> Cheers,
> Ada
>
>> On 12 Oct 2019, at 09:16, François Bonnarel <francois.bonnarel at astro.unistra.fr> wrote:
>>
>> Hi Petr
>>
>> Le 12/10/2019 à 01:14, Petr Skoda a écrit :
>>>
>>>> The term timeseries would not be enough by itself to know what the content of datalink is since it could be light curves (tabular data), images or spectra. These are the most common cases, and I would like to propose a common usage, e.g.:
>>>>
>>>> timeseries-lightcurve
>>>> timeseries-radialvelocities
>>>> timeseries-spectra
>>>> timeseries-images
>>>
>>> timeseries of images is in fact what we are presenting in our model in Fig.~13 - to every point of a light curve is associated the link to original image (here we were thinking about placing the provenenace )
>>>
>>> so the time series of images is just a normal time series (where another "axis" paralel with e.g. flux is an axis of mappings (links to images)
>>>
>>> As I have shown in Sydney 2015, the SPLAT , TOPCAT and ALADIN understand this well and (Fig.15 in a note) displays the image. We can even support cutouts ...
>>
>> But the point raised by Ada was not to address the case where you want to modelize this but more simply the case where you want to attach a timeSeries dataset to a source in a catalog (GAIA use case)
>> USING DAtaLInk
>>
>> Indeed, this is a vocabulary evolution problem. There is a proposal to extend DataLink vocabulary (semantics field) see (https://wiki.ivoa.net/twiki/bin/view/IVOA/UpdateDatalinkTerms) <https://wiki.ivoa.net/twiki/bin/view/IVOA/UpdateDatalinkTerms>
>>
>>
>> We should extend this  a little bit in the direction proposed by Ada
>>
>> Semantics working group will manage the procedure.
>>
>> Cheers
>> François
>>>
>>>
>>>
>>>
>>>>
>>>> Opinions or comments? Does this make sense to you?
>>>>
>>>> Ada
>>>>
>>>
>>> *************************************************************************
>>> *  Petr Skoda                         Tel   : (323) 649201, l. 361      *
>>> *  Stelarni oddeleni                          (323) 620361              *
>>> *  Astronomicky ustav AVCR, v.v.i     Fax   : (323) 620250              *
>>> *  251 65 Ondrejov                    e-mail: skoda at sunstel.asu.cas.cz <mailto:skoda at sunstel.asu.cas.cz>  *
>>> *  Ceska republika                                                      *
>>> *************************************************************************
>>
>
>

*************************************************************************
*  Petr Skoda                         Tel   : (323) 649201, l. 361      *
*  Stelarni oddeleni                          (323) 620361              *
*  Astronomicky ustav AVCR, v.v.i     Fax   : (323) 620250              *
*  251 65 Ondrejov                    e-mail: skoda at sunstel.asu.cas.cz  *
*  Ceska republika                                                      *
*************************************************************************