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Tim L edited this page Nov 1, 2016 · 50 revisions

How to map Wikipedia to DBPedia

For example, http://en.wikipedia.org/wiki/GOES_7 uses the "spaceflight" infobox. You can figure out what infobox it uses by clicking the page's "edit" tab to see the template syntax {{Infobox spaceflight in the source code. That infobox is defined at Template:Infobox_spaceflight and Wikipedians use it to describe satellites. When viewing the infobox at http://en.wikipedia.org/wiki/GOES_7, you can see the COSPAR ID is 1987-022A. We'll track that property-value through the DBPedia's mapping.

DBPedia's corresponding URI for http://en.wikipedia.org/wiki/GOES_7 is http://dbpedia.org/resource/GOES_7 (this greasemonkey script can help jump the gap from Wikipedia to DBPedia). Resolving DBPedia's URI shows dbpprop:cosparId 1987 (xsd:integer). The property's URI is http://dbpedia.org/property/cosparId, which doesn't really resolve to anything useful. DBPedia's mapping is controlled by editing http://mappings.dbpedia.org/index.php/Mapping_en:Infobox_spaceflight. To control the mapping, edit the page to put an occurrence of the http://mappings.dbpedia.org/index.php/Template:TemplateMapping.

TODO: http://mappings.dbpedia.org/index.php/OntologyProperty:CosparId. Keep an eye on "What links here" from a property page, so you know which other infobox mappings map to the DBPedia property.

Classes can be added to the DBPedia ontology by putting a Class template into e.g. http://mappings.dbpedia.org/index.php/OntologyClass:ArtificialSatellite (for http://dbpedia.org/ontology/ArtificialSatellite).

http://live.dbpedia.org/statistics/ can be used for some confidence that things aren't dead.

DBPedia's Mapping documentation

dbp vs. dbo

1 Nov 2016

Dear DBpedians,

To keep up with our two releases per year schedule, we are preparing the next release, due in March/April of next year. Therefore we are announcing our custom "Mapping Sprint" to encourage mapping activity to add new and improve/validate existing mappings until the end of this month.

As a lot of new languages and infobox-to-ontology mappings for various languages have already been entered by the mapping editors community into the DBpedia Mapping Wiki (http://mappings.dbpedia.org/) since the last DBpedia release, we hope to be able to provide clean data for even more infoboxes in even more languages with the new release.

Tasks:

  1. Could you please check whether the mappings that you have entered into the wiki over the last year still work correctly?
  2. If you still want to refine and extend mappings and/or the ontology, now would be the perfect time to do so.
  3. In order to help increasing the infobox coverage of the new release, it would also be great if you map additional templates or additional properties of existing templates to the ontology.

Also note that now we have separate issue trackers for the mappings and the ontology where we discuss design issues https://github.com/dbpedia/ontology-tracker/issues https://github.com/dbpedia/mappings-tracker/issues

For helping you see which widely used templates still require additional property mappings, we have updated the Mapping Wiki statistics for all languages: http://mappings.dbpedia.org/server/statistics/

Further functionality for testing and exploring the current mappings is available at: http://mappings.dbpedia.org/server/

for example mapping syntax errors http://mappings.dbpedia.org/server/mappings/fr/validate/*

New additions since the last sprint Redirects that need to be fixed (moved / merged) http://mappings.dbpedia.org/server/mappings/en/redirects/

Wrong mappings (according to our ontology). http://mappings.dbpedia.org/validation/

Wikidata mappings (create owl:equivalent classes & properties to Wikidata) http://mappings.dbpedia.org/server/ontology/wikidata/missing/

Examples For the English Wikipedia edition, you can see for instance at http://mappings.dbpedia.org/server/statistics/en/?show=100 that there is still room for improving the mappings.

The statistics for German, Spanish and French are found below and also still show lots of gaps for these important languages: http://mappings.dbpedia.org/server/statistics/de/?show=100 http://mappings.dbpedia.org/server/statistics/es/?show=100 http://mappings.dbpedia.org/server/statistics/fr/?show=100

You also have a possibility to see the list of errors for the current mappings, for instance for French you can validate either a specific mapping or all mappings at once http://mappings.dbpedia.org/server/mappings/fr/ http://mappings.dbpedia.org/server/mappings/fr/validate/* - error list for all French mappings

If you want to to refine and extend the ontology, note that you can add links between the DBpedia ontology and other schemata/ontologies, e.g. to schema.org or Wikidata as in the example below http://mappings.dbpedia.org/index.php/OntologyProperty:Author

Wikipedia infobox templates evolve over time and some of our mappings need to catch up as well. Some cases are simple where a simple move would do (double check the new mapToClass) while others require merging (we have a mapping both for the redirect and the target) http://mappings.dbpedia.org/server/mappings/en/redirects/

Invalid mappings report the use of properties in a mapping that does not comply with the property domain definition. In these case we could a) change the property and find a more appropriate one, b) broaden the domain of the property or c) adjust the class hierarchy (BE Carefull with this one!!!) http://mappings.dbpedia.org/validation/

Deadline We will use all mappings that are entered into the Mapping Wiki until Nov 30th for the upcoming DBpedia release.

It would thus be great if as many editors as possible participate in the mapping sprint and we as a community try to increase the mapping coverage as far as possible until this date.

Lots of thanks advance to all mapping editors who participate. Let's all try to make the next DBpedia release even better!

Cheers,

Markus Freudenberg, Dimitris Kontokostas, Sebastian Hellmann

20 March 2014

For more details on how DBpedia Live works I suggest you read the related publication [1]. Regarding the updates, we offer the dbpintegrator tool [2] that can sync your local triple store with DBpedia Live. This is the suggested option if you plan to make heavy use of the endpoint.

Once you have the syncing done,we now provide the following properties:

  • dbpedia-owl:wikiPageExtracted
  • dbpedia-owl:wikiPageModified that you can use to check for newly extracted pages.

DBpedia Live gets all information from the articles except from abstracts and images. Abstracts will be supported soon while for images we cannot offer real-time updates due to the current image Extractor architecture.

Best, Dimitris

[1] Mohamed Morsey, Jens Lehmann, Sören Auer, Claus Stadler, Sebastian Hellmann, (2012) «DBpedia and the live extraction of structured data from Wikipedia", Program: electronic library and information systems, Vol. 46 Iss: 2, pp.157 – 181 http://jens-lehmann.org/files/2012/program_el_dbpedia_live.pdf [2] http://sourceforge.net/projects/dbpintegrator/

23 Jan 2014

you can improve / increate the data that are extracted from Wikipedia by better mapping the infobox to the DBpedia ontology [1] [2] This is a crowdsourced process that needs regular updates due to changes in Wikipedia templates

Once you improve the mappings, DBpedia Live [3] will reflect all the changes (within a short time) but dbpedia.org will be updated on the next static release.

Best, Dimitris

[1] http://mappings.dbpedia.org/index.php/Mapping_en:Infobox_German_location [2] http://mappings.dbpedia.org/server/templatestatistics/en/?template=Infobox_German_location [3] http://live.dbpedia.org

8 Dec 2013

  • dbp: is a legacy namespace for properties. (i.e. "raw infobox data")
  • dbo: is the current namespace for properties.

So, universities in countries

prefix dbpedia: <http://dbpedia.org/resource/>
prefix dbo:     <http://dbpedia.org/ontology/>
prefix dbp:     <http://dbpedia.org/property/>

select ?country count(distinct ?university) as ?count
where {
           ?university dbo:type dbpedia:Public_university ;
            dbp:country ?country .
           filter (isIRI(?country))
}
group by ?country
order by desc(?count)

7 Dec 2013

If you restrict yourself to the DBpedia ontology, you'll get much more sensible results. E.g., if you execute this query on the DBpedia SPARQL endpoint (http://dbpedia.org/sparql) (which includes the prefix dbpedia-owl: http://dbpedia.org/ontology/):

 select ?country (count(?university) as ?count)
 where {
   ?university a dbpedia-owl:University
   optional{ ?university dbpedia-owl:country ?country}
 }
 group by ?country

you get much better results. For more about the differences, see this StackOverflow question (http://stackoverflow.com/q/17237144/1281433), and some of the DBpedia documentation that the answer links to.

Two other cases where the noise in the raw infobox data affected people's results:

http://stackoverflow.com/q/16977418/1281433 http://stackoverflow.com/q/18834426/1281433

-Josh Taylor

DBPedia tables

12 Dec 2013

Petar Ristoski set up a web page where all classes from the DBpedia ontology are available for download as separate .csv and .json files.

14 Nov 2013

Announced the first version of DBpedia as Tables

DBPedia Live

12 Dec 2013

http://live.dbpedia.org announced update

DBPedia dumps

older

http://dbpedia.org/downloads states the dumps we use for the latest version and http://downloads.dbpedia.org/ holds a dump archive

for the latest updates you can refer to live.dbpedia.org (might be unresponsive due to maintenance)

-Dimitris

Lookup service

http://lookup.dbpedia.org/

the service is working as expected. The results are ordered by RefCount (i.e., how often the respective Wikipedia article is linked from another one) in descending order. By default, the service returns the top 5 results, and http://dbpedia.org/resource/Building is simply not among those.

Try http://lookup.dbpedia.org/api/search.asmx/KeywordSearch?QueryString=building&MaxHits=100, and you will find what you are looking for.

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