[ Re: Vocabularising dataproduct_type] an attempt for definitions for catalog and source list

[Baptiste Cecconi]

Hi Mireille and all, 

> Le 24 mars 2020 à 15:58, Mireille LOUYS <mireille.louys at unistra.fr> a écrit :
> 
> Hi Baptiste , 
> If we can extend the notion of what is the object we consider as a source, I guess we can accomodate most of the objects of Vespa/EPNTAP with the same  catalog definition . After all it seems it deals with some quantity of light detected for an object, astronomical object, solar regions , asteroids, planet, regions on a planet etc.. ( just a global perspective offered here to gather all possible sources) . 
> 
If you remove the "some quantity of light detected" part, yes, we could probably agree on some definition. In solar and planetary sciences, we don't do only "light", we also measure particles or more generically matter (mass spectrometer detectors, drilling on martian rocks, physical samples from meteorites, or from sample return space missions, in-situ meteorological parameters in the atmosphere of a planet or a moon…). 
> "events" however are a special category of Obscore dataproducts, defined at the time with the Xray event lists in mind. 
> it requires columns for a time stamp. 
> it is organised as a list of events if necessary
> It is stored in some formats like VOTable, ascii tables, etc. or specific formats as used for planetary data like CDF, FITS, etc. 
> Do you think we could consider 'event' or 'event list' instead of 'catalogs of events' in the Planetary domain? 
> 
The types "event" and "event list" are two different things, since in the first case, the object is a single event instance, where in the second case, the object is composed of several events. We already have "event", for distributing events (one at a time). When we specify both dataproduct types (Catalog+Event), then it means that we have what you propose to name an "event list". 

This brings me to this question: what is the intrinsic difference between a "catalog" and a "list" in the current context of IVOA dataproduct_types ? 

Cheers,
Baptiste

> that would help to put vocabularies in sync , as I mentionned in my previous emails.
> Cheers, Mireille
> Le 24/03/2020 à 14:10, Baptiste Cecconi a écrit :
>> In VESPA/EPNcore, we use the Catalog term with a similar definition, but with a wider scope when it comes to the set of individual objects the catalog is related to. Any type of target (planet, moon, asteroid, sample…), location on target, events. 
>> 
>> By the way, our equivalent of Measurement would be Catalog Item. This means that the primary information is in the current record (i.e., in the current row for a TAP service), instead of relating to an remote URL for the information (i.e. through an access_url column for a TAP service). 
>> 
>> Baptiste
>> 
>>> Le 24 mars 2020 à 11:06, Mireille LOUYS <mireille.louys at unistra.fr <mailto:mireille.louys at unistra.fr>> a écrit :
>>> 
>>> hi all, 
>>> here is my suggestion for the term catalog as it has been used so far in the VO
>>> 
>>> catalog:
>>> a set of physical quantities recorded from an observing/simulation process and measured/computed for a set of individual astronomical objects (sources).
>>> Each catalog entry corresponds to one individual source object. 
>>> The usual representation is a table with columns figuring the quantities and rows representing an entry.
>>> 
>>> source list:
>>> 
>>> a catalog where entries are derived from one or a restricted set or data products : single image, multiband image, radio or hyperspectral cube, eventlist for instance. 
>>> Typically, ObsTAP can handle source list as dataproducts, with coverage inherited from the progenitor dataset.
>>> 
>>> On the contrary very large catalogs like survey, hips catalogs with coverage='allsky' are managed within archives/datacenters and searched on with keywords from the astronomical semantics, like type of objects, regime, instrument types, survey name, etc.
>>> 
>>> Here is an interface example: http://cdsarc.unistra.fr/viz-bin/cat <http://cdsarc.unistra.fr/viz-bin/cat>
>>> Are there server applications distributing such all sky catalogs with Obscore as one single dataproduct? 
>>> best , Mireille
>>> 
> --
> Mireille Louys,  MCF (Associate Professor)  
> CDS				IPSEO, Images, Laboratoire Icube 
> Observatoire de Strasbourg	Telecom Physique Strasbourg
> 11 rue de l'Université		300, Bd Sebastien Brandt CS 10413
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