VOUnits 1.0 RFC: 2014 January 7 to 2014 February 4

The last VOUnits RFC implied a small collection of document and implementation changes which, it turned out, had consequences more far-reaching than was immediately apparent. As well, some new participants appeared in the discussion at this point. The result is a set of document and syntax changes which, it has been decided, are substantial enough to warrant a new RFC.

The most recent version is http://www.ivoa.net/documents/VOUnits/ (version 1.0-20140226)

The differences between version 1.0-20131224 and 1.0-20140226 are minor wording and layout changes. There are a few further very minor changes which can be found in the repository version, and which will be included in the next published release (after TCG review).

The main visible changes in version 1.0-20131224 are

• the appearance of 'quoted units', thus permitting for example km/'martianDay' (see the document for discussion; this was the principal syntactic change which ended up necessitating the new version)
• recognition for unknown functions, so that for example dBA(ct/s) includes an unknown function dBA; this is explicitly permitted by the standard, though a parser should make available the information that the function is not a recognised one
• the appearance of binary prefixes (Ki, Mi, ...) on certain units
• more explicit statements that the indication that units are unknown is the special string unknown, and that the indication that a quantity is dimensionless is that the units string is the empty string
• various textual clarifications to the document.

The editors believe we have accommodated or acknowledged each of the concerns on the original RFC page, either in the document or on that page. Please feel free to disagree.

We do not believe these are deep changes in principle, so those WG chairs who were happy with the document in its previous incarnation may not need to examine it too closely this time.

Changes are reported in Appendix D of the new version of this proposed recommendation, available below.

Comments from all working groups members are welcome. Comments should be on this page; discussion should be on the semantics@ivoa.net list.

For comparison, and as a reminder, all comments from the previous iteration are available on the former VOUnitsRFC page. The previous PR document was 1.0-20130724 (there was also a distributed version PR-1.0.20130922, and an intermediate Working Group draft, 1.0-20131025, which is attached to this page). All previous versions are available on the IVOA documents page.

#All WG Review

Comments

Applications WG (MarkTaylor, PierreFernique)

Data Access Layer WG (PatrickDowler, FrancoisBonnarel)

Data Model WG (JesusSalgado, OmarLaurino)

Grid and Web Sevices WG (AndreSchaaff, AndreasWicenec)

Registry WG (GretchenGreene, PierreLeSidaner)

Semantics WG (NormanGray, MireilleLouys)

The Semantics WG approves this version.

Data Curation & Preservation IG (AlbertoAccomazzi, FrancoiseGenova)

Education IG (MassimoRamella, SudhanshuBarway)

Knowledge Discovery in Databases IG (GeorgeDjorgovski)

Theory IG (FranckLePetit, RickWagner)

Time Domain IG (JohnSwinbank, MikeFitzpatrick)

Comments from TCG (WG and IG chairs)

• PR-VOUnits-1.0-20131025.pdf: Recommendation for Units strings in the virtual Observatory -UPDATE