Pedro Osuna wrote:
> I am worried though about allowing the identifier "ivoa:" as namespace
> for those UCDs already approved but temporarily out of the UCD
> standard
> (as this one will only be updated once or twice a year).
Section 2 of the v1.1 UCD standard seems to state that "ivoa;" is equivalent to the default namespace. It is unclear what distinction is being drawn here between "approved" and "not yet standard". On the other hand, I am very heartened that the UCD committee(s) have reached the point of recognizing that at least some alternative namespaces are necessary.
> A possible solution for this problem would be to allow for specific
> namespaces for specific needs (let's say, like a "solar:" namespace
> for
> solar physics specific UCDs)
The standard already does: "The use of namespaces, indicated by the presence of a colon in the word, is possible..." This is also discussed in section 2, which goes on to attempt to dissuade their use: "but should be avoided as far as possible." I believe this to be a vain hope. The way to control the looming complexity of UCDs is precisely to spread the responsibility (and pain) around.
This reminds me of the "image" extension specification for FITS, which tries to convince users that it is both bad - and worse, unnecessary - to create data-less primary header data units. What did the community immediately do with image extensions? I'm tempted to leave that as a rhetorical question - but what we did was to discover an excellent usage for subclassing metadata between the primary headers and the extension headers and for stuffing all the data into the extensions.
UCD namespaces are inevitable.
Bob Mann wrote:
> My only comment on this is to ask whether it is better to have
> each RFM sent out to the Scientific Board as soon as it is submitted
> or whether they should be collected over a period (three months?)
By all means, although I might suggest a monthly cadence. There should also be a mechanism for expedited discussions for UCDs which are needed "yesterday". Note, however, that the pressure for immediate decision-making would also be relieved by the availability of namespaces.
Rob Seaman
National Optical Astronomy Observatory
Received on 2005-10-19Z14:03:55