Saturday, May 25, 2019

Citation.js: Wikidata Update

Citation.js: Wikidata Update

The new update, v0.4.4, contains a few Wikidata improvements (commit):

  • 22 new mappings
  • 2 fixed mappings (ISSN did not work and publisher-place was mapped to the wrong thing)
  • 2 improved mappings (container-title for chapters and more URL mappings)
  • 1 removed mapping (genre was inconsistent with the intended use, although it followed the specification)

Because most of these mappings require additional resources (recipient has to fetch people, review-* has to fetch the review subject and original-publisher-place has to fetch the country and location of the publisher of the original version of a work) this would have caused a lot more requests to the API. It is a good thing, then, that there is a new resolver in place, which pre-fetches such information for all requested works at once.

This has to be done in levels; you cannot fetch the country if you do not have the location, the location requires the publisher and to find out the publisher you have to have the work already. However, temporarily ignoring the cap of 50 items per request, the number of requests is now only based on those levels (which is at most five), instead of the number of claims requiring additional requests.

For example, item Q21972834 (Assembling the 20 Gb white spruce (Picea glauca) genome from whole-genome shotgun sequencing data) takes:

  • 6 requests in v0.4.0-rc.2, before requests for properties were grouped (so it would make a request for every author)
  • 3 requests in v0.4.3: one for the work, one for the authors, and one for journal
  • 2 requests in v0.4.4, which includes a bunch of new mappings that would have cost a total of 5 requests in the previous version

Grouping the requests from all works has the added benefit of not having to fetch the same author and journal info repeatedly — which can be quite common for bibliographies. For example, the bibliography of Groovy Cheminformatics with the Chemistry Development Kit, currently containing 74 items, takes 11 requests in the new version. For the same bibliography, the previous version would make at least 150 requests — for each item one for all the authors and one for the journal — and probably more than that.

[core] GET {}  
[core] GET {}  
[core] GET {}  
[core] GET {}  
[core] GET  480%7CQ1709878%7CQ900502&format=json&languages=en {}  
[core] GET {}  
[core] GET {}  
[core] GET {}  
[core] GET {}  
[core] GET {}  
[core] GET {}  

However, I do notice slightly more requests with a low number of items than I would expect. I will look into that.

Conference papers in Wikidata

Part of the mappings that were added in the recent update are the event-* properties, i.e. “name of the related event (e.g. the conference name when citing a conference paper)” (spec). Finding out how those are modelled in Wikidata proved a bit of a challenge, as most instances of Q23927052 (conference paper) are published in proceedings with the book type. To get some numbers (query):

type typeLabel items
Q571 book 715
Q5633421 scientific journal 676
Q1143604 proceedings 315
Q16024164 medical journal 53
Q23927052 conference paper 48
Q1002697 periodical literature 32
Q41298 magazine 29
other other 61

48 conference papers are published in conference papers? That does not seem right. But maybe they just have the wrong type, but still link to the event? Well no, not really (query).

hasEvent items
false 1952
true 6

Luckily, the information is not lost: usually, the label contains location and date information about the event, although extracting that would be probably be a tedious task. However, perhaps there are a lot of proper proceedings out there, but the articles linked to it just have the wrong type (query)?

type typeLabel items
Q13442814 scholarly article 3513
Q23927052 conference paper 315
Q3331189 version, edition, or translation 11
Q1143604 proceedings 9
Q10885494 scientific conference paper 7
Q1980247 chapter 6
Q191067 article 5
Q18918145 academic journal article 4
Q333291 abstract 3
other other 10

That seems to be the case: most works that are published in instances of proceedings are tagged as instances of scholarly articles, and only nine are tagged as both. And: relatively many have events linked to them (query).

hasEvent items
true 2692
false 1184

That’s better. I’ll look into working together with WikiCite to work on the rest.