Hi!
Then what happens with the
"unit":"1" that currently we have in JSON? It
seems that one cannot enter this string in the field, and I guess it
would (rightly) be invalid as a unit. Will Wikibase continue to use this
(invalid) string as a placeholder for "no unit"?
We could make a bot to convert those to Q199. RDF export already does
it. Of course, not all of them are actually unit-less values, some of
them may be something that actually needs a unit, so we could wait for a
while to give people a chance to fix that and then convert the remaining
ones to Q199.
If every wiki needs to define its own unit items to
see labels, how is
data exchange supposed to work? Will the RDF export then contain a
different IRI for "meter" when exporting data from Wikidata and from
Commons (or whatever other future instance)?
That's a very interesting point, I think this can be handled by
establishing:
1. Types/classes of units, such as "measure of length"
2. Designated standard unit - e.g. "meter" is a "standard measure of
length".
3. Conversion properties - e.g. "foot" is 0.305 "meters"
4. Having RDF exports contain values converted to standardized measures
- i.e. every quantity that has unit that is "measure of length" will
also have a value expressed in "meters".
Then reconciling data between instances would be just reconciling
properties for the above (which can be made easier by finding some
existing ontology featuring units and relating to it), and then matching
entities for standard measures.
--
Stas Malyshev
smalyshev(a)wikimedia.org