License discovery service for RDF documents

This post describes a service to discover the license in a RDF file (ontology, dataset, etc.).

The service is available by providing the URI (see Service #1 at http://licensius.appspot.com) but it is also provided as a RESTful service, very easy to be invoked:

The name of the service is as follows:



How O is the LOD cloud? (revisited)

This post updates the analysis of the licensing practices in the datasets in the LOD cloud. Different snapshots of this reality were taken in 2009, in 2012 and 2013, which I summarized in a previous post. This is the LOD cloud diagram coloured by type of license:


RDFLicense: a dataset of licenses in RDF

RDFLicense is a dataset of 126 licenses (suitable for general works, data, etc.) expressed as RDF. The official URI of the dataset is:


While the dataset is also accesible at datahub:


An ODRL2.0 RDF editor

Tools need to be developed for new specifications if these are to be adopted.

Valid as a proof of concept and even useful for editing simple expression, a Simple ODRL Editor has been released at OEG (Universidad Politécnica de Madrid).

The tool is based on a Simple ODRL API, still under development...

The Simple ODRL Editor permits creating rights expressions,


Media Contract Ontology

The Media Contract Ontology is an ontology for representing contracts dealing with exploitation rights of audiovisual works. The ontology is a standard approved in 2013 --with already one ammendment-- and its specification is a document for which you have to pay.

Yet, for an informal description, we forward you to an informal description, divided in two namespaces:


ODRL 2.0

The Open Digital Rights Language (ODRL) Ontology has been released as a Draft!

Check it out and provide comments!


Linked Data Rights vocabulary

Following the work done here, the new vocabulary Linked Data Rights has been published.
It supersedes the first attempt, done in August...

The schema is as follows:

Examples of use

To declare an ontology licensed as CC-BY

You don't need LDR.


Licensing example for an RDF mapping

This post is about RDF mappings and licensing, and proposes the following example for its discussion.


To void or not to void

The next figure shows the general concept of data vs metadata (data about the data).

Licensing a database is expressing some information (the license) about another information resource (the database).
In a W3C note, the "Vocabulary of Interlinked Datasets (VoID)" was described as a vocabulary for expressing metadata of RDF datasets.
This generates two alternative locations for declaring the license of a given dataset.


Loading large RDF in Virtuoso

This post describes how to load many nquads in Virtuoso.

Previous info

Why do you want this

Lets imagine you have many RDF triples (or nquads) and want to expose them in a server.

About nquads

RDF triples are very famous. I can easily state I am a person:

<http://victor.rodriguez.doncel.name> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://xmlns.com/foaf/0.1/Person>

RDF quads add context information, in a fourth component. This can be the name of the graph.



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