On a possibly related note, I just tried a similar query for the things with the largest diameter, and got no results. What did I do wrong?

https://query.wikidata.org/#PREFIX%20ps%3A%20%3Chttp%3A%2F%2Fwww.wikidata.org%2Fprop%2Fstatement%2Fvalue%2F%3E%0A%0ASELECT%20%3Fitem%20%3FitemLabel%20%3Fsize%20WHERE%20%7B%0A%20%20%3Fitem%20p%3AP2386%2Fps%3A2386%2Fwikibase%3AquantityAmount%20%3Fsize%20.%0A%20%20SERVICE%20wikibase%3Alabel%20%7B%0A%20bd%3AserviceParam%20wikibase%3Alanguage%20%22en%22%20.%0A%7D%0A%7D%20ORDER%20BY%20DESC%28%3Fsize%29%20LIMIT%2010

You have ps:2386 instead of ps:P2386 in the second query.

@Nikki ha, right, thanks! Much better now!

Ok, so clearly, Q1 should be on top of that list!

https://query.wikidata.org/#PREFIX%20psn%3A%20%3Chttp%3A%2F%2Fwww.wikidata.org%2Fprop%2Fstatement%2Fvalue-normalized%2F%3E%0A%0ASELECT%20%3Fitem%20%3FitemLabel%20%3Fsize%20WHERE%20%7B%0A%20%20%3Fitem%20p%3AP2386%2Fpsn%3AP2386%2Fwikibase%3AquantityAmount%20%3Fsize%20.%0A%20%20SERVICE%20wikibase%3Alabel%20%7B%0A%20bd%3AserviceParam%20wikibase%3Alanguage%20%22en%22%20.%0A%7D%0A%7D%20ORDER%20BY%20DESC%28%3Fsize%29%20LIMIT%2010

Similar to wikibase:statements, don't we have to wait a year till every item was edited?

That doesn't seem to be the problem here, I edited light year earlier after seeing this ticket, but the query in the description still doesn't include it.

Q14916719 length is expresses in parsec, and parsec is not part of the configured units in unitConversionConfig.json. I guess it was either rare or failed some other criteria when we created the initial config. I think that's the reason. We can add it anytime certainly and add the new statements for it, we have the code now.

Note that for efficiency, only units directly in unitConversionConfig.json are considered for conversion, we don't try to build a chain when creating RDF (creating the config itself does chains, so maybe we should just rerun the config generating script).

Q1 should be on top of that list!

I don't see "diameter" property on Q1.

Just noting that I think rare(r) units eventually should be supported. Just maybe not right now. We need to decide how we want to proceed with this - incorporating both more units (such as mass, etc.) and rarer units. Eventually I'd like every unit that is used to be there, but it's OK if it takes time.

I just did a bit of research with Daniel on the next steps. This seems best to me:

• Add support for main units for:
  • mass/weight
  • area
  • speed
  • volume
  • duration
• let the community test and try
• ask for which dimensions they need most in addition to what is available then
• ask for which units for the supported dimensions they need most in addition to what is available then

Sounds great, let's make the tasks :)

What about light year? It has a length statement with the unit in metres, so shouldn't it appear in the query in the description?

Is the list of supported conversions visible somewhere? https://www.mediawiki.org/wiki/Wikibase/Indexing/RDF_Dump_Format#Normalized_values is rather vague about what is/isn't included.

@Nikki The list of supported units is here:

https://phabricator.wikimedia.org/diffusion/OMWC/browse/master/wmf-config/unitConversionConfig.json

The RDF format docs do not mention it because it's a config, so it can change any time. We plan to update it to include more units.