DM-1/DAL-1 combined session, 19-Sep-2006, 9:20-10:50

Institute of Astronomy, Moscow


Agenda
- Spectral Access

    1. Jonathan McDowell - Spectrum DM (30m)
    2. Doug Tody - SSA Protocol (30m)

- Discussion of SSA and Spectrum DM (30m)

Minutes: Markus Dolensky

check also Wiki for presented slides
http://www.ivoa.net/twiki/bin/view/IVOA/IvoaDataModel
http://www.ivoa.net/twiki/bin/view/IVOA/InteropSept2006DAL



1.) 
Jonathan McDowell reports on Spectrum data model update (V0.98) and focuses mainly on
user feedback posted to the list http://www.ivoa.net/forum/dm/

comment: XML Elements should be nillable (as opposed to empty)

Q: How to describe data formats?
A1: For SSA serialization currently 3 specific formats are defined; one each in 
FITS, VOTABLE, XML
A2: GWS group should propose a more general answer also in the context of VOSpace

Q: How to express not available vs. not known?
A: It requires a different convention in each format and requires some more investigation.



ToDo
====

- make "redshift" definition more strict; object to wavshift term because redshift
is more widely recognized term

- need to accommodate coordinates that are not in ICRS system like for solar data.
  
- about GROUP vs. use of TABLE elements in VOTable serialization
  F. Bonnarel suggests to put forward a different example



2.)
Doug Tody reports on SSA IF document update


about VERSION parameter:
- could use different service endpoint instead of VERSION parameter
- to clarify how to deal with compatible versions

- ICRS as default: could be spelled out explicitly


Implementation efforts 'not' listed on relevant slide

Verification:
- like at NCSA also Igor Chillingarian is planning a SSA verification service

reference implementation:
- Astrogrid client is planned (on top of 5 listed ones) but schedule has to be checked
- IAP, France, is working on an SSA implementation as well