The product-type vocabulary

[Markus Demleitner]

Hi Dave,

On Thu, Dec 16, 2021 at 12:01:49PM +0000, Dave Morris wrote:
> The proposed vocabulary mixes singular and plural terms.
> 
> The term is event (singular), but the label and description are for eventS
> (plural).

That's easily fixed (it's just a label), and since I consider a
difference between identifier and label less desirable than the
slight awkwardness of having "Event" mean "a collection of [...]
events", I've already committed it (volute rev. 6063).

> Most of the other terms are singular, cube, image, spectrum, time-series,
> visibility etc. but measurementS is plural.

That's harder to fix, as that's coming down from obscore, and
changing the identifier would perspectively mean changing what's in
dataproduct_type.  So... I guess we can't really change this (but
as I said, I'd like to get rid of the whole concept anyway, as it is
ill-defined, and it's unclear how it would relate to all the others
(which are, after all, measurements as well).

> The example use-case given in the description of the vocabulary uses the
> plural term "spectra" in the discovery query, but the target term in the
> vocabulary, "spectrum", is singular.

That language has been a remnant of that earlier experiment, and I've
removed it as well in rev. 6063.  Having said that, I'd say plural
nouns in *descriptions* may be a good idea ("a collection of
events").

> So a discovery query for a collection of images would search for 'image' and
> a query for a collection or stream of events would search for 'event' as the
> product type.

I tend to agree that labels and identifiers in this particular
vocabulary ought to be chosen so that they're singular; they will be
used to say what a single thing is, after all.  In that vein, "event"
(that I'm rather sure would in general refer to files containing
quite a few event*s*) probably should have been called
event-collection in obscore.

        -- Markus