[Heig] HEIG Obscore Note - ready for final review- part Uses-cases

[Mireille Louys]

Dear HEIG ,

Here is another set of remarks for the Usecase part :
/*UseCases.tex :*/

*Uses-cases assumptions on vocabularies : *
We have proposed to distinguish 3 categories of datasets in this note.
Observation datasets, typically in HE : event-lists, and response 
function datasets, and advanced datasets.

In agreement with Semantics WG we have 3 vocabularies :
http://www.ivoa.net/rdf/product-type used for data products served in 
/ivoa.obscore/ table
http://www.ivoa.net/rdf/response-type to expose response data products
The draft for an advanced data product vocabulary is discussed here:
https://github.com/ivoa-std/VEPs/pull/21/changes/c4195e1975341881d8fda22cb851ff11b5b74c1f#top

Note that the Radio astronomical community also requires the definition 
of new dataproduct types for their science ready datasets as « advanced 
dataset ».
See https://www.sciencedirect.com/science/article/pii/S2213133725000769

The note naturally insists to distinguish between the kinds of datasets,
due to their role in the science interpretation process.
But to serve all these datasets by an ObsTAP service we need to define
an implementation strategy compatible to all HEIG projects  and stable 
for future data archives.

Currently the Uses-case Appendix A shows 3 strategies:

  * *Assumption 1*: /dataproduct_type/ in /ivoa.obscore/ belongs to any
    of the 3 vocabularies product-type,
    advanced_data_products, response data products:

All products are distributed with the /ivoa.obscore/ table .
Chandra A.1.8, A.2.1,A.2.3, A2.4 , CTAO: A1.9, SWGO: A1.3
Pb: If you search event-list or light-curves in a region, with response 
functions,
you get all datasets together and need to sort which psf matches which 
light curve for instance. 

You can use GROUP by obs_id for instance, but still there may be several 
light curves involved in the region,
so how to match light_curves and psf files properly if the psf varies in 
the field of view?

  * *Assumption 2*: /data_product_subtype/ in /ivoa.obscore/ provides
    the type of response function
       and "response-function" is added to product_type vocabulary.

All products are distributed with the ivoa.obscore table .
Km3net A1.10, A1.13
Chandra
Pb: dataproduct_subtype is not standard in ObsCore and left open for 
archives’ specific needs .
No distinctions between response and maps ( excess maps , significance 
maps, etc)
also proposed in the dataproduct_subtype category.

  * *Assumption 3*: separate the 3 kinds of products and implement one
    table for each kind

    /ivoa.obscore/  uses data product_type in product-type vocabulary
    /ivoa.response /uses data product_type in response-type vocabulary
    /ivoa.adp/ uses data product_type in advanced-dataproduct-type
    vocabulary

The ObsCore data model shows the links between the various dataset 
categories.
See Fig class-diagram-ObscoreExtensiondesign_for HE_interop2025v1 
presented in Görlitz in
EN-ObscoreExtensiondesign_for_HE_interop2025v1.pdf here 
<https://wiki.ivoa.net/internal/IVOA/InterOpNov2025DM/ObscoreExtensiondesignForHE-interop2025-Louys.pdf> 


Data discovery can then query  each table separately, or join them to 
discover the links between these 3 types of products.
Here is an example:
"Provide me all advanced datasets, light curves and spectra for one 
region in the sky."

Select obs_publisher_did, dataproduct_type, adp_publisher_did, 
adp_product_type
FROM ivoa.obscore as c
JOIN ivoa.obscore-adp as adp
ON adp.obs_publisher_id = c.obs_publisher_id
WHERE c.dataproduct_type LIKE ‘%light-curve%’
OR c.dataproduct_type LIKE ‘%spectrum%’
AND (position constraint)

*Loose criteria in queries *
Select * is used on all uses cases and may deliver a very wide table
with empty values in many columns or redundancy between a response
taken as an ObsCore record and the related observation.
It is recommended in ObsTAP to keep the parameter list short like in the 
example above,
and to use the result table for a finer query afterwards.

*Relationship between response functions and the ivoa.obscore-hea table*

Many of our use cases show systematic JOIN between /ivoa.obscore/ and 
/ivoa.obscore-hea/
tables when searching for response function. 
This may lead to 
ambiguities as for instance, I suppose ev_xel is a property for an 
event-list but not for a psf or edisp response function. 
Is this right ?
Any example of the interest of joining response and ivoa.obscore-hea, to 
provide another use-case?

More exploration is probably needed to set up working examples for these 
uses cases.

I plan to have a pull request ready on our github by wednesday, with 
some proposal to update the text.

Thanks, Mireille

Le 12/08/2026 à 11:08 PM, Janet Evans via heig a écrit :
> Dear HEIG,
>
> Apologies for the long gap in communication.  Here is a summary of 
> some of the things that have happened since our last HEIG meeting.
>
> o IVOA Interop in Strasbourg
> Great meeting for HEIG with interest in the Obscore extension, a 
> plenary to present the HE Obscore extension doc details and the demos 
> prepared by this group.
> o Semantics meeting at Interop
> Several of us met with the Semantics WG to settle several vocabulary 
> keywords - it was a good meeting
> o Further Obscore Note input and final review/scrub
> There is a new section 6 along with a vocabulary update and scrub for 
> typos/etc.
>
> It’s now your turn to review the document as we prepare to turn it 
> over to the TCG/Exec for Endorsed Note status.
> Here’s the schedule we’re working to:
> Wed, Aug 12 — Janet sends notice of final doc to HEIG for review 
> (typos/minor edits, no new content)
> Tue, Aug 25 — End of HEIG review/feedback
> Thu, Aug 27 — Janet sends note to TCG with request for review/endorsed 
> status
>
> The document is available in GitHub 
> (https://github.com/ivoa/HighEnergyObsCoreExt?tab=readme-ov-file); 
> I’ve also appended the PDF below.
>
> Best regards,
> -janet
>
>
> *Janet Evans | Software Development Manager | Chandra X-ray Center*
> Center for Astrophysics | Harvard & Smithsonian
> Office: (617) 495-7160
> 60 Garden Street | MS 81 | Cambridge, MA 02138
>
>
>
>
-- 
--
Mireille Louys, MCF (Assistant Professor)
Centre de données Astronomiques (CDS)       Equipe Images, ICube
Observatoire de Strasbourg                  Telecom Physique Strasbourg
11, rue de l' Université                    300, Bd Sebastien Brandt CS 10413
F-67000 Strasbourg                          F-67412  Illkirch Cedex
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