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Introduction: What is Wikidata?

Wikipedia?

  • Remember life before Wikipedia?

  • "An encyclopedia that anyone can edit"

Wikimedia

{width=80%}

Wikidata

  • knowledge base

  • it's a wiki

  • community model

Motivation

  • link Wikipedia language editions

  • reuse statements across Wikipedia projects

  • provide complex query capabilities

It's awesome, especially if you're into data!

Overview: Structure of Wikidata

Statements

Factual claims are stored as statements

subject -- predicate -- object

thing -- relationship -- thing

item -- property -- value

Similar to RDF (and mapped to its model)

Entities

Independent of language (identifiers vs. names)

  • entities, labels, descriptions, statements

  • types of entities

    • items (have wiki-links)
    • properties (have data types and constraint statements)
    • lexemes

Wakeup task

Find item of your home town, school...

  • Statement details

    • properties
    • qualifiers
    • references

More information

http://bit.ly/wikidata-onepage

https://www.wikidata.org/wiki/Wikidata:In_one_page

Wikidata and identifiers

Action: Editing Wikidata

Task 1: Try out!

In groups of 2-3:

  • add/extend Wikidata items on some of your professors

  • see existing professor items as boilerplates

  • collect questions for afterwards

Magic: Using Wikidata

Case study: Astrolabes explorer

Case study: WikiCite and Scholia

Wikidata Query Service

More Tools

Outlook: What comes next?

Wikimedia Commons

  • more than 55 million media files

  • not as shiny as Instagram, YouTube, Flickr...

  • but Open Content, no commercial interest!

  • community model

  • quite "unstructured"

Structured Data on Wikimedia Commons

Migration of Wikimedia Commons to Wikibase (2017-2019)

  • every media file is an entity

    • multilingual media file captions
    • statements about media files

  • properties reused from Wikidata, e.g. depicts (P180)

  • work in progress (e.g. no SPARQL yet)

More information at https://commons.wikimedia.org/wiki/Commons:Structured_data

Lexicographical data

Intoduction of three new types of entities in 2018:

  • Lexemes (L)
  • Forms (F)
  • Senses (S)

https://www.wikidata.org/wiki/Wikidata:Lexicographical_data

Sample application: http://auregann.fr/derdiedas/

Summary: What to know about Wikidata

Know the basic structure of Wikidata

  • entities, labels, descriptions, statements

    • items (have wiki-links)
    • properties (have data types and constraint statements)
    • lexemes

  • statements

    • property
    • qualifiers
    • references

Know how to query Wikidata

  • Wikidata query service (SPARQL)

  • Several tools and programming libraries

  • (big) data dumps

Know the limits

  • Coverage is very inconsistent

  • Data modeling is instable

  • Qualifiers and references help to improve quality

    • but not used as much
    • harder to query

  • Working with Wikidata is like doing data science:
    cleaning data & fighting with software

Know that it's a community

  • People are not paid

  • Nobody has a full overview

  • Tools (plenty!) come and go

  • Be nice and allow misunderstandings