Linked Data
From CKAN
There are a number of activities that combine CKAN and Linked Data, including:
- The lodcloud group on the Data Hub, which collects metadata for hundreds of datasets published as Linked Data, and is the basis for the iconic Linking Open Data Cloud diagram.
- semantic.ckan.net is a website that re-publishes the contents of various CKAN instances, including the Data Hub, as Linked Data.
- There are activities around federation of data catalogs, including CKAN instances, with the RDF-based dcat vocabulary that is in development at W3C.
To support these activities, the Data Hub community organizes regular online meetups.
Contents |
News
- Next community meetup: February 2nd, 2012. See below for details.
- November 17, 2011: Successful Community Meetup on LOD Cloud! Etherpad notes
Online meetups
Every couple of months via Skype and IRC. Dates are announced on ckan-discuss.
Next meetup
- February 2nd, 2012, at 5pm GMT. Sign up and agenda on the Etherpad!
Previous meetups
Organizers
- Richard Cyganiak
- Anja Jentzsch
- Mark Wainwright
- Irina Bolychevsky
Would you like to present something at a future meetup? Get in touch!
The lodcloud Group
The lodcloud group on the Data Hub is a curated group that contains metadata for hundreds of datasets published according to the Linked Data principles. Metadata is checked for completeness and (to some extent accuracy) by a team of curators before any dataset is added to the group. The group's data is used to create the Linking Open Data Cloud diagram, and to drive a number of other visualizations and metadata-based applications.
Documentation for this effort is somewhat scattered:
- Group page on the Data Hub
- Main website for the diagram, including FAQ
- Guidelines for Collecting Metadata on Linked Datasets in CKAN
- CKAN record validator
Artefacts produced from this data include:
- lod-graph, a graph-based visualization produced by Ed Summers
- SPARQL Endpoint Status, an uptime tracker by Mondeca Labs
- dsi.lod-cloud.net
CKAN metadata as RDF: semantic.ckan.net
Semantic.ckan.net is a metadata repository aggregator that presents a unified RDF view over a number of CKAN instances, including the Data Hub. Semantic.ckan.net provides a SPARQL endpoint.
Contact: William Waites
Catalog federation with W3C's Data Catalog Vocabulary (dcat)
To do
Acknowledgements
OKFN is a member of the LOD2 project, an EU-funded research project on large-scale Linked Data infrastructure for open and enterprise data. Cataloguing efforts that collected and updated LOD data set metadata at TheDataHub.org have been supported by the EU-funded projects PlanetData and LATC, and described at http://www4.wiwiss.fu-berlin.de/lodcloud/state/
Actions from 2011-11-17 Meetup
- Keith to look into creating the converter to get native dcat/VoID into the CKAN API
- Richard (with Anja, Pablo) to come up with HTML form capturing the lodcloud metadata
- Richard to write a script that takes existing links from extra fields and turns them into proper relationships using the API
- Comments on making the API better would be well received ;-)
- Pablo and Pierre-Yves to explore a metadata enricher that adds additional fields (number of triples, vocabularies used) by looking at the dumps that are already listed
- Pierre-Yves to add pointers to his work to http://wiki.ckan.org/Contrib
- Rufus to add some links to quick&dirty CKAN bulk import scripts to http://wiki.ckan.org/Contrib
