User:SebastianHellmann/ontology

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Please look at the discussion on Wikipedia:Village_pump_(technical)#DBpedia_Template_Annotations and Wikipedia:Requests_for_comment/infobox_template_coherence. SebastianHellmann 12:03, 12 November 2009 (UTC)

DBpedia is a community project for extracting structured information from Wikipedia and make if freely available on the Web. We refer to the main article and the project website for a full description. The purpose of this page is to explain the DBpedia ontology and its relation to Metawiki.

What is the DBpedia Ontology?[edit]

The DBpedia ontology is based on OWL and forms the structural backbone of DBpedia. It describes classes, e.g. person, city, country, and properties, e.g. birth place, longitude. Information in Wikipedia articles is then mapped to this ontology. Most prominently, many Wikipedia pages use so called infoboxes. For instance, the English wikipedia article about London contains a "settlement infobox". This infobox may be mapped to e.g. the class "populated place" in the DBpedia ontology and the attributes in the infobox are mapped to properties in the DBpedia ontology. Please see the documentation of the settlement infobox for details. This way, a unified view over all data in infoboxes can be obtained, which is not limited to the English Wikipedia. Since this information conforms to Semantic Web standards, it can be queried and combined by a broad range of tools in a useful way. This increases the value of information entered by the Wikipedia community.

How is the DBpedia ontology maintained?[edit]

So far, few people inside the DBpedia project maintained the ontology, but in the spirit of open source projects, control over the ontology will be handed over to the Wikipedia community. For each entity (e.g. a class or property) in the ontology, a page with the URL http://meta.wikimedia.org/wiki/DBpedia/ontology/$entity is created. Such a page contains information in OWL format about the entity. Each of those pages contains a link back to this general description. Two examples are Person and birthPlace.

A complete overview of all existing entities is available at DBpedia/ontology-overview.

(editor comment: We have the chicken and egg problem that the approach will fully work only after creating DBpedia ontology pages, but need to document them before their creation such that they are not instantly deleted. For this reason, this page will remain in draft status for the next days or weeks. We kindly ask administrators to grant us sufficient time to document the effort.)

How do Wikipedians benefit from the DBpedia ontology?[edit]

Wikipedia uses hundreds of infoboxes for describing various entity types like NFL teams, schools in Canada, train stations etc. These infoboxes are separated and do not use a common vocabulary, e.g. several different spellings are used for infobox attributes which all stand for the birth place of a person (birth_place, birthPlace, origin). By linking those to a single property on MetaWiki, it is possible to have a unified view over information in Wikipedia. For instance, you can browse through browse persons born in the USA in 1970, query for famous German musicians born Berlin etc. In this way, we provide added value for the information collected by Wikipedians. The ontology does not only allow to connect data from infoboxes within Wikipedia, but is also connected to other knowledge bases like UMBEL and OpenCyc, which allows to combine information from different sources.

Currently, it is also quite difficult and troublesome to identify factual inconsistencies (such as outdated population figures, conflicting birth days etc.) in Wikipedia. The ontology can help Wikipedia authors to identify such inconsistencies, since they e.g. connect the attribute born used in one template with birthday in another. In the short term, this will be a very powerful instrument for Wikipedia authors to cross check information on a large number of pages, in the medium-term this can evolve into more advanced search and querying interfaces and in the long-term establish Wikipedia as a central hub on the emerging Semantic Web.

Why should those ontology related pages be created on Metawiki?[edit]

According to the MetaWiki inclusion policy, the following points are in favor of creating those pages on MetaWiki:

  • DBpedia is project based on Wikipedia and collaborating with its community. WikiMedia has granted DBpedia free and full access to their live update stream such that the project can extract information with only a few minutes delay.
  • It is multilingual, i.e. the ontology is not language specific, and therefore should not be part of any Wikipedia language edition. It connects several Wikipedia language editions.
  • It is primary research regarding wiki projects.

If you are in doubt whether DBpedia ontology pages belong here, we kindly ask you to please use the discussion page instead of deleting the articles right away.

Quick start Guide[edit]

The sub-page-name of any wiki-page in DBpedia/ontology may be used to provide additional information about a corresponding resource in the dbpedia:ontology namespace. Information is provided via the use of special templates, namely Template:DBpedia ObjectProperty, Template:DBpedia Class, and Template:DBpedia DataProperty. For correct use only one of these templates may appear on a subpage in the DBpedia/ontology namespace. Any information provided through the template will be added to the corresponding DBpedia resource.


How to use the templates[edit]

Basically, using the templates is very simple:

  • Create an appropriate sub-page.
  • Add one of the three already mentioned templates to it.
  • Provide values for some of the template parameters.

Also, transcluding any of these templates will put a link on the site which points to the DBpedia live extraction server where you can check the extracted values. The DBpedia live extraction will recognize changes in usually less than a minute.

Here is a list of all parameters that are used by the DBpedia templates. Paremeters which allow a language tag (so far only rdfs:comment and rdfs:label) may be named parameter@languageTag. This will automatically associate the language tag with the argument value. The parse type indicates how template arguments are interpreted. The default value will only be used if the parameter is not used or no value is given otherwise it will replaced.

parameter allows language tag parse type default value
rdfs:comment yes text
owl:disjointWith no mos-list
rdfs:domain no mos-list
owl:equivalentClass no mos-list
owl:equivalentPropert no mos-list
rdfs:label yes text
rdfs:range no mos-list
rdfs:seeAlso no mos-list
rdfs:subClassOf no mos-list owl:Thing
rdfs:subPropertyOf no mos-list


Parse Types:

  • text
    The argument will be parsed as plain text.
  • mos-list
    The argument is interpreted as a comma separated list of class-expressions in Manchester OWL-Syntax (MOS) e.g. Plant Or Animal. Each expression separated by comma is treated as an individual statement.
    This means that commas are not e.g. replaced by "Or" to form a single expression. Therefore values such as "Plant, Animal" and "Plant Or Animal" result in different RDF to be generated.
    For Spam-protection reasons you may not use URIs in the MOS-expressions. You may however use any of the predefined namespaces.

Examples[edit]

Here is a short list of pages which use the DBpedia templates:

Person is an example for the use of Template:DBpedia Class.

birthPlace is an example for the use of Template:DBpedia ObjectProperty.