Last modified: 2014-06-30 09:26:15 UTC
Some quantity properties "intrinsically" have exact values - like the number of people in a parliament, the number of planets in the solar system, etc. It's confusing to users that Wikibase will guess a margin of uncertainty of +/-1 in such cases. Considering that this guess would be correct for e.g. the number of square meters in a room, we can't use a general rule for avoiding this problem. We need some kind of hint to the parser what heuristic to apply for guessing the uncertainty. That hint could be a) A per-property flag (possibly represented by a claim) b) A separate "amount" or "number" DataType, which would also use QuantityValue, but would have different parsing rules from the "quantity" DataType used for measured values. Note btw that "population" is a natural number count but should *not* default to exact values, but apply the +/-1 rule.
Sorry if this is the wrong bug. It appears the same problem occurs from the database. When I wbsetclaim a quantity with value amount:+0.044405586 , it returns successful, but the value is amount:+0.04440558599999999689345031583798117935657501220703125 https://test.wikidata.org/wiki/Q484?action=history
s/database/API/
Still unclear to me why there is any "margin of uncertainty" by default at all. The quantity value is extracted from a reference. It is each particular reference that defines the margin. If there is no margin specified by the reference, there is no way to guess what the margin would be. And still, that is what is trying to be achieved here with even more complicated logic. How would one determine that 100 has an uncertainty margin of 1, 10 or 100 if it is not stated by the reference?
