User:Epìdosis/Wikidata-intro

Another video (in Italian): live editing sull'ontologia di Wikidata
summary: 1) how it works, 2) why it is important, 3) how to find and try to solve issues

how it works
- comparison: AAT (thesaurus: only concepts), VIAF (authority file: only individual entities), Wikidata (both concepts and individual entities)
  - e.g. mosaic: mosaic (Q133067): image or writing made from an assemblage of small pieces of colored glass, stone, or other materials vs AAT 300015342 vs BNF 11977798g vs BNCF 13084 vs LCSH sh85087419
1. ontology (Q324254): specification of a conceptualization in computer science and information science
2. Wikidata:WikiProject Ontology
3. the main visualization tool: Wikidata Graph Builder
4. (Wikidata:Notability)
5. Help:Basic membership properties crucial guide
  1. crucial properties
    1. instance of (P31): that class of which this subject is a particular example and member; different from P279 (subclass of); for example: K2 is an instance of mountain; volcano is a subclass of mountain (and an instance of volcanic landform)
    2. subclass of (P279): this item is a subclass (subset) of that item; all instances of this item are instances of that item; different from P31 (instance of), e.g.: K2 is an instance of mountain; volcano is a subclass of mountain (and an instance of volcanic landform)
    3. part of (P361): object of which the subject is a part (if this subject is already part of object A which is a part of object B, then please only make the subject part of object A), inverse property of "has part" (P527, see also "has parts of the class" (P2670))
  2. other useful properties
    1. opposite of (P461): item that is in some way the opposite of this item
    2. different from (P1889): item that is different from another item, with which it may be confused
    3. partially coincident with (P1382): object that partially overlaps with the subject in its instances, parts, or members
    4. said to be the same as (P460): this item is said to be the same as that item, though this may be uncertain or disputed
why it is important
1. in itself, to classify entities (like a thesaurus)
2. in general, to make inferences
  - e.g. engineers vs. engineers + subclasses
  - e.g. churches in Italy vs. churches in Italy + subclasses
  - e.g. persons having worked in a museum vs. persons having worked in a museum + subclasses
how to find and try to solve issues
1. a list of issues: Wikidata:WikiProject Ontology/Issues (from File:WikidataCon 2021 - Overview of ontology issues.pdf)
2. issue prioritization: Wikidata:Ontology issues prioritization (File:Wikidata ontology issues — suggestions for prioritisation 2023.pdf)

Statistics (on 18-06-2023) on items (total: 104 328 421; without both properties: 2 442 134) containing:

Property	in total	with the other	without the other
instance of (P31)	100 425 738	2 544 693	97 881 045
subclass of (P279)	2 899 745	2 544 693	355 052

consequently, the ontology of Wikidata is constituted by ca. 2.9 M items (overview)

> item created as example (20-06-2023): ancient mosaic (Q119789177)

User:Epìdosis/Wikidata-intro

Contents

Authority control - basic edit

Introduction edit

Structure edit

Authority control edit

GLAM - basic edit

Introduction edit

Use on Wikipedia edit

Some cases edit

Practice - basic edit

Storia e struttura edit

Alcuni usi dei dati edit

General - basic edit

Introduction edit

Use on Wikipedia edit

Structure edit

Visualizing data edit

Queries edit

Editing data edit

Guidelines edit

Comunità di Wikidata edit

Wikidata community edit

Ontology edit

See also edit