CODEWITHSUNDEEP
sparqlsemantic-web
harry potter
harry potter

Reputation: 350

Ontologies on linked open data cloud

I am currently working on the Linked Open Data cloud and would like to know whether it is possible to have the ontologies of datasets present in the LOD cloud.

Upvotes: 2

Views: 221

Answers (1)

Jakub Kotowski
Jakub Kotowski

Reputation: 7571

Publishing in the Linked Open Data cloud is as easy as making your data publicly available for example as RDF, as HTML, via a SPARQL endpoint, ...

To spread awareness about your data, so that people can use it and link to it, describe your data according to Guidelines for Collecting Metadata on Linked Datasets in CKAN and add it to datahub.io (a canonical CKAN installation).

For an intro about publishing open data have a look at Richard Cygniak's presentation. A comprehensive guide is the Linked Data: Evolving the Web into a Global Data Space book.

Linked Open Data normally contain both ontologies and instance data. I don't think that the ontologies of LOD datasets are available separately. There are various ontology repositories: Where can I find useful ontologies? Ontology repositories list at W3C but none of them are really comprehensive and really well maintained as far as I know.

For most datasets, you should be able to get the ontology by dereferencing its namespace URL. For example if I take the arbitrary LOD dataset http://datahub.io/dataset/oferta-empleo-zaragoza/resource/6704184d-42e3-4778-a576-826f1d3672e2 I can see that it starts with:

<rdf:RDF
    xmlns:j.0="http://purl.org/dc/terms/"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
    xmlns:j.1="http://purl.org/ctic/empleo/oferta#" >

So if you point your browser to http://purl.org/ctic/empleo/oferta# it will redirect to http://data.fundacionctic.org/vocab/empleo/oferta.html which is the HTML description of the ontology which also links to an RDF representation: http://data.fundacionctic.org/vocab/empleo/oferta_20130903.rdf

The namespace URL has content-negotiation configured so you can get the ontology in RDF directly if you set the header "Accept: application/rdf+xml" for the get request:

curl -LH "Accept: application/rdf+xml" http://purl.org/ctic/empleo/oferta#

Upvotes: 4

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