IVOA Semantics Working Group

The Semantics Working Group (Charter) superseded the UCD Working Group in 2006 as it was realised semantic resources beyond UCDs were required. To this day, the main focus of the Semantics WG is the maintenance and development of Vocabularies.

The WG is an open association communicating via our mailing list that you are welcome to subscribe to. We also host roughly bimonthly SemanticsCalls, which are open to all interested parties.

The group is managed by

WG Chair MarkusDemleitner (2019-)
WG Vice-chair CarloMariaZwoelf (2019-)
WG Chair emeritus MireilleLouys (2015-2019)

Current Activities

  • *** New*** Request For Comments for proposed Endorsed Note UCD 1.4 UcdList1point4RFC
  • Vocabularies in the VO, version 2: This defines a modernised framework for vocabulary production and consumption. It is currently in the stage of a working draft. The update procedures proposed are already being tried out; cf. VEPs.
  • UCD List Maintenance: UCDListMaintenancePage
  • revision for solar data UcdSolarDiscussion

Unique identifiers and description for facilities and instruments in astronomy and planetary science (started 2014)

Unified names and identifiers for astronomical Facilities, Telescopes and Instruments: See Unified Facilities Description at UniFacil (on going work).

TelescopeInstruments Nomenclature Meetings:

  • @ the Lisa conference in SXB -2017-June 3-6
  • Meeting in Strasbourg @CDS - 2018-Feb-21-23 SxbNomenTIMeeting20180221-23
  • Preparation for discussion at AAS meeting January 6-10 2019 - Metadata structure for Telescopes and Instruments description MetaTelInst -

Former work

Items here are occasionally moved to UCDandSemanticsFormerWork.

Towards Vocabularies 2

In preparation to the effort of modernising the Vocabularies in the VO specification, a page was set up to try a comment process for updating the datalink vocabulary, UpdateDatalinkTerms. While this should no longer be used for discussion, the proposals and comments are for now kept for when they will enter a new-style process.

Also, VocabularyTestPage was a now deprecated effort to provide the vocabulary index now on http://www.ivoa.net/rdf.

New UCD List v 1.3

Elaboration of new UCD keywords for planetary metadata and radio data. This effort is described on the discussion page PlanetaryUCD .

This has generated a loop for revision for the UCD list of terms , now in the final step of Recommendation.

See http://wiki.ivoa.net/twiki/bin/view/IVOA/UCDList2017RFC for the request for comments for http://www.ivoa.net/documents/UCD1+/20170831/index.html.

Units specification in the IVOA

VOUnits: This specifies how to express unit strings in VO documents, APis, protocols and interfaces.

  • The VOUnits document is now an IVOA REC. The VOUnitsRFC and DiscussionOnVOUnits pages still exist, but should not now be added to.
  • There are no immediate plans for further work on the standard, however there is a small collection of issues and suggestions at VOUnitsNext


Ontology of Astronomical Object Types
text: WD_2007-02-19.pdf
OWL file (2008MAY16): ObjectTypes_0.99r.owl

SKOS to OWL script. Basic, but functioning


  • General working-group discussion archive. See the UCD archive for discussion prior to June 20th, 2006.
  • UCD Scientific Board archive
  • UCD Technical Board archive.

Related pages - ongoing work- discussions -maintenance


Topic attachments
I Attachment Action Size Date Who Comment
PDFpdf Note-UCDlistMaintenance-2.0-20170602.pdf manage 219.8 K 2017-06-02 - 13:33 FrancoiseGenova UCDlistMaintenance V2.0, Note 2 June 2017
PDFpdf Note-UCDlistMaintenance-2.0-20170602_withchanges.pdf manage 271.3 K 2017-06-02 - 13:34 FrancoiseGenova Note UCDlistMaintenance V2.0, showing changes from V1.20
PDFpdf PR-UCDlistMaintenance-2.0-20171018.pdf manage 362.1 K 2017-10-19 - 21:26 MireilleLouys Maintenance Process for the IVOA UCD list
PDFpdf PR-UCDlistMaintenance-2.0-20180823withchanges.pdf manage 253.0 K 2018-08-23 - 09:48 FrancoiseGenova  
Unknown file formatxsd VOFacility.xsd manage 28.9 K 2015-11-20 - 18:15 MireilleLouys VOresurce extension for the description of VOFacilities: Telescope , space missions , etc. - XML schema
PDFpdf WD-UCDlist-1.3-20150608.pdf manage 748.3 K 2015-06-18 - 13:02 MireilleLouys WD for updated UCDs terms / planetary and solar data
Unknown file formatdocx WD-UCDlist-1.3-20160719.docx manage 85.9 K 2016-10-21 - 06:16 MireilleLouys update on UCD 1.3 WD
PDFpdf WD-UCDlist-1.3-20160719.pdf manage 811.9 K 2016-10-21 - 07:07 MireilleLouys update of UCD vocabulary/ pdf version
PDFpdf WD-UCDlistMaintenance-2.0-20171018-Trackmode.pdf manage 365.8 K 2017-10-20 - 16:10 MireilleLouys maintenance Process for UCD- WD
XSL (XML style sheet)xsl skosToOwl.xsl manage 5.2 K 2010-11-15 - 19:49 BrianThomas SKOS to OWL script. Basic, but functioning.
Topic revision: r100 - 2021-06-24 - BaptisteCecconi
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