A picture is worth a thousand words, we often say, yet many areas are in demand of sophisticated visualization techniques, and the Semantic Web is not an exception. The size and complexity of ontologies and Linked Data in the Semantic Web constantly grows and the diverse backgrounds of the users and application areas multiply at the same time. Providing users with visual representations and intuitive interaction techniques can significantly aid the exploration and understanding of the domains and knowledge representedby ontologies and Linked Data.

Ontology visualization is not a new topic and a number of approaches have become available in recent years, with some being already well-established, particularly in the field of ontology modeling. In other areas of ontology engineering, such as ontology alignment and debugging, although several tools have recently been developed, few provide a graphical user interface, not to mention navigational aids or comprehensive visualization and interaction techniques.

In the presence of a huge network of interconnected resources, one of the challenges facedby the Linked Data community is the visualization of multidimensional datasets to provide for efficient overview, exploration and querying tasks, to mention just a few. With the focus shifting from a Web of Documents to a Web of Data, changes in the interaction paradigms are in demand as well. Novel approaches also need to take into consideration the technological challenges and opportunities given by new interaction contexts, ranging from mobile, touch, and gesture interaction to visualizations on large displays, and encompassing highly responsive web applications.

There is no one-size-fits-all solution but different use cases demand different visualizationand interaction techniques. Ultimately, providing better user interfaces, visual representations and interaction techniques will foster user engagement and likely lead to higher quality results in different applications employing ontologies and proliferate the consumption of Linked Data.

These and related issues are addressed by the VOILA! workshop series concerned with Vi-sualization and Interaction for Ontologies and Linked Data. The third edition of VOILA! is co-located with the 16th International Semantic Web Conference (ISWC 2017) and will take place as a full day event on October 22, 2017 in Vienna, Austria. It will be organized around scientific paper presentations and discussions, and will be accompanied by interactive software demonstrations, giving developers a chance to gather feedback from the community.

The call for papers for VOILA! 2017 attracted 20 submissions in different paper categories. At least three reviewers were assigned to each submission. Based on the reviews, we selected 13 contributions for presentation at the workshop in the following categories: full papers (10), position papers (2) and experience papers (1).

We thank all authors for their submissions and all members of the VOILA! program committee for their useful reviews and comments. We are also grateful to Aidan Hogan and Valentina Presutti, the workshop chairs of ISWC 2017, for their continuous support during the workshop organization.

September 2017

Valentina Ivanova, Patrick Lambrix, Steffen Lohmann, Catia Pesquita