Direct Manipulation for Information Visualization
There is a tremendous effort from the Information Visualization (Infovis) community to design novel, more efficient or more specialized desktop visualization techniques. While visual representations and interactions are combined to create these visualizations, less effort is invested in the design of new interaction techniques for Infovis. In this thesis, I focus on interaction for Infovis and explore how to improve existing visualization techniques through efficient yet simple interactions. To become more efficient, the interaction techniques should reach beyond the standard widgets and Window/Icon/Menu/Pointer (WIMP) user interfaces.
In this thesis, I argue that the design of novel interactions for visualization should be based on the direct manipulation paradigm and the instrumental interaction framework, and take inspiration from advanced interactions investigated in HCI research but not well exploited yet in Infovis. I extract from the HCI literature a large set of principles, benefits and challenges of direct manipulation interfaces that have been proposed and discussed over the last 30 years, that I classify into three high level overlapping categories: Learning, Ease of use, and Seamless and fluid interaction. Then I describe and evaluate several exemplar visualization techniques according to these criteria. I describe multiple projects I have designed based on these principles and benefits, to tackle direct manipulation challenges, illustrating how opportunistic interactions can empower visualizations. I explore design implications raised by novel interaction techniques, such as the tradeoff between cognitive congruence (the natural mapping between user's intent and action) and versatility (of the interaction techniques), the problem of engaging interaction (how to make the user engaged and willing to explore the visualization), and the benefits of seamless, fluid interaction. Finally, I provide design guidelines and perspectives, addressing the grand challenge of building or consolidating the theory of interaction for Infovis.