During Fall 2020 Interop we had a session, requested by Markus Demleitner, that aimed at opening a wide discussion on both Measure and Coordinate models and possibly at refining their usages.

This came after a long discussion on the mailing list, related to the necessity of keeping or not a tight dependancy between Measurements and Coordinates. It has also been suggested that product models (e.g. CubeDM ) could be replaced with domain related components.

Many people have participated to the discussion with many positive contributions.
Although the goal of this message is not to report on that meeting, we do need to note a few points:

  • There is a clear demand for using models
  • There is a clear demand for the models to be simple and modular.
  • The distinction between what is modelling and what is serialisation is unclear.
The need for a concrete solution for annotating catalog data, that resurfaced last week, has been tackled by the WG for a couple of years along with the development of Meas/Coordinates models.
  • 2018:Discussions have been engaged on this topic after a hands-on session in Victoria.
  • 2019: We asked data providers and client developers to present their needs in a dedicated session at Paris
After these 2 surveys the scope of the model usage has been exposed in Virtual May 2020 and we have been working on MANGO (model for source data with some MC adaptations ) that has been sketched in Groningen and in virtual-May and then presented in November 2020.

To continue this action we have been organising a virtual workshop (initially proposed by Tom to the TCG) with the hope of getting a widely accepted framework.

The idea is not to start afresh but to give to the participants the opportunity of matching their needs with the current proposals.

To get a clear picture of what has to be done, we propose to work with a variety concrete use cases, mostly taken out of the SourceDM proposal ( 2016) and data samples provided by interested people.


  • 2021 February 18: Public release of the use-case repository.
  • 2021 February 24: Running meeting to present the process
  • 2021 March: People can look and contribute at the repository
  • 2021 April: Virtual Workshop.

Running meeting(25/02/2021)

  • Etherpad [[https://yopad.eu/p/dm_virtual_meeeting_#2-365days][link]

DM meeting - Workshop preparation - collective remarks and minutes
Participants 15

  • Mirreille Louys, Tom Donaldson Laurent Michel, Mark CD, Jesus Salgado, Gilles Landais, Francoise Genova, Kai Polsterer, Marco Molinaro, Francois Bonnarel , FX Pineau, Carlos Rodrigo, Sara Bertocco, Vincenzo Galluzzi, Markus Demleitner
The purpose of this meeting is to prepare the DM workshop forseen in April 2021:
Workshop goals
LM presents the goal of the meeting. Preparation of meeting on data models on VO and how
to improve consensus on data modeling generation.
Some DMs work well but disagreements on how to match models with scientific quantities.
Proposal to solve mapping problems is MANGO, developed by LM
Also, proposal from Tom D. to organize a workshop on how to solve this gap
Proposed process to prepare the workshop
Gather a list of concrete use cases and possible solutions
Gather contributions
  • propose new use cases
  • comment the use cases
  • propose a solution
  • comment proposed solutions
The dm-usecases repository
These use cases is created compiling some VO historical use cases that require data modeling
Two folders per use case, raw_data with an annotated xml and another folder with a mango proposal
fulfilling the use case
Time line for contribution to the use cases repository is during March to allow the pull requests merging
of all the contributions
poll created on use cases portal:
FB: Procedure is to create a branch and ask for a pull request to be merged by LM? yes, either for commenting
existing or creating a new use case
TM: Lack of consensus are, in my view, due to the level of implementation of the solutions
LM: I contacted Mark T. about using data models in Topcat and the problem comes from heteregeneous data
modeling annotations in VOTables
FG: It is difficult to decide whether to implement before having an idea of the work required to implement
This means that the point has to be central to the workshop using the use cases
MD: Will implement. If it works for VizieR, it will work for him.
TM: Use case for proper motion representation?
LM: Yes, in astrometry
Mark CD: Orbital models not present, a new use case is needed
MD: Not clear if we need models for quantities as this could be solved just with UCDs
FB: UCDs are standalone, DM informs about quantities.
MD: physics: UCDs, use DM to annotate
GL: Mango enables to link two different quantities together, no need to have a specific model for each case.
Workshop conduct
virtual / in person ?
Proposal and decision for a Date
  • End of April ?

DM meeting - Workshop preparation - collective remarks and minutes - Second session
Participants 8: Laurent Michel, Mireille Louys, Gregory Dubois-Felsmann, Jesus Salgado, Francois Bonnarel, Gerard Lemson, Tom Donaldson, Mark Allen, Harry Enke
LM presents objective of propossed workshop and historical background
poll created on use cases portal:
Use cases page proposed:
GL: Is there a DM behind all the MANGO annotations?
LM: totally free
Changes to be done in another branch (to be merged with trunk after review)
If a specific model is proposed , a new directory should be inserted
Same if a new mapping strategy is proposed

Topic revision: r3 - 2021-02-25 - LaurentMichel
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