Hi!
Also, I don't see a reason why the JSON encoding should use an IRI
It probably doesn't have to, just Q-id would be enough. "1" is OK too, but a bit confusing - if the rest would be Q-ids, then it makes sense to make all of the Q-ids. Other option would be to make it just null or something special like that.
string does not seem to help anyone. I would suggest keeping the "1" as a marker for "no unit". Of course, this "1" would never be shown in the
It is possible, but "1" the looks like "magic value", which is usually bad design since one needs to check for it all the time. It would be nicer if there could be a way to avoid it.
Wikibase and elsewhere. If we create a special IRI for denoting this situation, it will be better distinguished from other (regular) units, and there will be no dependency on the current content of Wikidata's Q199.
We already have such dependencies - e.g. in calendars and globes - so it won't be anything new. But let's see what the Wikidata team thinks about it :)