Dear DBpedians,
We will start preparing the next DBpedia release this month. In the
meantime, as for every release cycle, we need you to lay last hands on the
mappings (see below). Yet, this time will be the last in which mapping
editors have to rely on the Mapping Wiki (http://mappings.dbpedia.org/
<http://mappings.dbpedia.org/index.php/Main_Page>) for editing. Shortly
after the end of this sprint we will freeze the wiki and introduce the Git
based RML mappings editor. Wouter Maroy
<https://www.linkedin.com/in/wouter-maroy-746810114/>, Anastasia Dimou
<http://rml.io/people/AnastasiaDimou.html>, Ben De Meester
<http://users.ugent.be/~bjdmeest/> and Pieter Heyvaert
<https://pieterheyvaert.com/research/> from Ghent University did make
tremendous progress in preparing the RML-based extraction, while Ismael
RodrÃguez <http://ismaro3.github.io/> developed the Mappings UI in the
course of our ongoing GSoC projects. Many thanks to all involved.
*RML*
The RDF Mapping language (RML - http://rml.io) is a generic scalable
mapping language defined to express rules that map data in heterogeneous
structures and serializations to the RDF data model. RML is defined as a
superset of the W3C-recommended mapping language, R2RML
<https://www.w3.org/TR/r2rml/>, that maps data in relational databases to
RDF. RML also introduces the possibility of proper validation before data
generation which leads to improved data quality. For integration in
DBpedia, RML was extended to operate with a new data source, Wikipedia
infoboxes. Generating the DBpedia mappings dataset by defining the mappings
in RML is a more sustainable approach.
The current RML mappings are translated mappings from the Mapping Wiki and
are stored in a GitHub repository
<https://github.com/dbpedia/mappings-tracker>. The last translation will be
performed after this Mapping Sprint. The new UI for editing RML mappings is
currently a work in progress, but a preview can be found here:
http://mappings-ui.herokuapp.com/.
Relevant publications:
Declarative Data Transformations for Linked Data Generation: the case of
DBpedia <https://biblio.ugent.be/publication/8525863/file/8525869.pdf>
Assessing and Refining Mappings to RDF to Improve Dataset Quality
<http://ceur-ws.org/Vol-1690/paper97.pdf>DBpedia Mappings Quality
Assessment <https://biblio.ugent.be/publication/8133269/file/8133271.pdf>
*Mapping Sprint*
Until we switch to the RML editor, we would like to ask all members of the
mapping editors community for their help with the upcoming DBpedia release
in the form of a *MappingSprint*:
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 to increase 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 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.
http://mappings.dbpedia.org/validation/
*Deadline*
We will use all mappings that are entered into the Mapping Wiki until
*August 31st* for the upcoming DBpedia release.
Thus, it would 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, Wouter Maroy and Sebastian Hellmann.
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