Meas/Coord/Tranf: Status & Discussion
(Tuesday May 5, 22:00-23:00 UTC)

Session notes:

    Presentation from Mark Cresitello-Dittmar
    https://wiki.ivoa.net/internal/IVOA/InterOpMay2020DM/MCT_status_2020a.pdf

    Participants: 27

Questions

(write your "Name: my question?" in this list)

Laurent: How are you? (example)
T.Jenness: Is there is a standard serialization and only there is a reader that tries to understand the Coordsys output of a certain server, what is the role of the IVOA models?
Rep: G.Lemson: not possible 100% accurate serialization on VOTable. Discussion on exercises done in YAML
F.Bonnarel: Common representation/language allows any transformation
T:Jenness: AST could be very useful for analyzing all he myriad FITS WCS formalisms. It can read in many different FITS WCS representations and could be used as a translator from FITS WCS to IVOA XML but it would need to be taught how to write that XML (which is easier than being taught to read it).
Tom D:  Minor point on the possible PyVO implementation.  There is an existing SkyCoord.guess_from_table() method (https://docs.astropy.org/en/stable/api/astropy.coordinates.SkyCoord.html#astropy.coordinates.SkyCoord.guess_from_table).  There have already been requests for getting this to work for the current conventions on RA/Dec and Coosys in VOTable, so this might be a good place to try the new implementation as well.  I.e., The question is Astropy core versus PyVO.  If it needs too much dependency on VO-specific stuff, maybe it won't belong in PyVO, but it would be great if Astropy users who don't even know they're using a VOTable could get a good guess at coords.
PatD: Energy axes is not in the model
MCD: Not enough core to be included into the model. Maybe these axis should be in Cube, Source or similar

G.Lemson: Relationship between Coord system and coord space should be discussed at certain point
MCD: It can be discussed in a future review of the specs

G.Lemson: in general, without a 1 to 1 serialization, it is difficult to evaluate the annotations (YAML? JSON?)
MCD: Examples in VOTable and XML (Although not totally 1 to 1)

J.Evans: We need real implementations more than examples. LSST has done a good exercise to develop transformations in line with the models but it is not generally adopted

P.Dowler: Which is the killer app to use these models?
MCD: Iris project
G.Lemson: Crossmatch between catalogues (doing correct transformations) would be  a great use case and IVOA could provide support on this
MCD:  We are entering in a different phase where models are not only used by access protocols but also
 using the serializations to do transformations