Public administration is working to ensure access to open data, in order to empowering citizens in their right to information. Aligned with this objective, the European open data portal (data.europa.eu) references a large volume of data on a variety of topics.

However, although the data belong to different information domains or are in different formats, it is complex to exploit them together to maximise their value. One way to achieve this is through the use of RDF (Resource Description Framework), a data model that enables semantic interoperability of data on the web, standardised by the W3C, and highlighted in the FAIR principles. RDF occupies one of the top levels of the five-star schema for open data publishing, proposed by Tim Berners-Lee, the father of the web.

In RDF, data and metadata are automatically interconnected, generating a network of Linked Open Data (LOD) by providing the necessary semantic context through explicit relationships between data from different sources to facilitate their interconnection. This model maximises the exploitation potential of linked data.

It is a data sharing paradigm that is particularly relevant within the EU data space initiative explained in this post.

RDF offers great advantages to the community. However, in order to maximise the exploitation of linked open data it is necessary to know the SPARQL query language, a technical requirement that can hinder public access to the data.

An example of the use of RDF is the open data catalogues available on portals such as datos.gob.es or data.europa.eu that are developed following the DCAT standard, which is an RDF data model to facilitate their interconnection. These portals have interfaces to configure queries in SPARQL language and retrieve the metadata of the available datasets.

A new app to make interlinked data accessible: Vinalod.

Faced with this situation and with the aim of facilitating access to linked data, Teresa Barrueco, a data scientist and visualisation specialist who participated in the 2018 EU Datathon, the EU competition to promote the design of digital solutions and services related to open data, developed an application together with the European Publications Office.

The result is a tool for exploring LOD without having to be familiar with SPARQL syntax, called Vinalod: Visualisation and navigation of linked open data. The application, as its name suggests, allows you to navigate and visualise data structures in knowledge graphs that represent data objects linked to each other through the use of vocabularies that represent the existing relationships between them. Thus, through a visual and intuitive interaction, the user can access different data sources:

• EU Vocabularies. EU reference data containing, among others, information from Digital Europa Thesaurus, NUTS classification (hierarchical system to divide the economic territory of the EU) and controlled vocabularies from the Named Authority Lists.
• Who's Who in the EU. Official EU directory to identify the institutions that make up the structure of the European administration.
• EU Data. Sets and visualisations of data published on the EU open data portal that can be browsed according to origin and subject.
• EU publications. Reports published by the European Union classified according to their subject matter.
• EU legislation. EU Treaties and their classification.

The good news is that the BETA version of Vinalod is now available for use, an advance that allows for temporary filtering of datasets by country or language.

To test the tool, we tried searching for data catalogues published in Spanish, which have been modified in the last three months. The response of the tool is as follows:

And it can be interpreted as follows:

Therefore, the data.europa.eu portal hosts ("has catalog") several catalogues that meet the defined criteria: they are in Spanish language and have been published in the last three months. The user can drill down into each node ("to") and find out which datasets are published in each portal.

In the example above, we have explored the 'EU data' section. However, we could do a similar exercise with any of the other sections. These are: EU Vocabularies; Who's Who in the EU; EU Publications and EU Legislation.

All of these sections are interrelated, that means, a user can start by browsing the 'EU Facts', as in the example above, and end up in 'Who's Who in the EU' with the directory of European public officials.

As can be deduced from the above tests, browsing Vinalod is a practical exercise in itself that we encourage all users interested in the management, exploitation and reuse of open data to try out.

To this end, in this link we link the BETA version of the tool that contributes to making open data more accessible without the need to know SPARQL, which means that anyone with minimal technical knowledge can work with the linked open data.

This is a valuable contribution to the community of developers and reusers of open data because it is a resource that can be accessed by any user profile, regardless of their technical background. In short, Vinalod is a tool that empowers citizens, respects their right to information and contributes to the further opening of open data.