Comparison is an essential part of data analysis and, therefore, of many visualization tasks. While the published literature provides a wealth of visualization tools for looking at individual objects (graphs, volumes, time series, gene sequences, molecular motions, etc.), there has to date been less consideration of support for comparison. The PIs argue that comparison tasks are best supported by tools explicitly designed for that purpose. The problem is that visual comparison becomes more challenging as the number of objects, their size, and the complexity of the objects and/or of the relationships among them increases. The difficulty is further compounded by our rapidly growing ability to collect and generate data. In prior work the PIs have developed some encouraging initial examples of comparison tools, but these are specialized successes that offer little guidance for future endeavors. Addressing a wider range of comparison problems at greater scale with our present limited understanding thus largely remains an art that requires considerable effort. The PIs' goal in this project is to move towards a science of visual comparison. By studying visual comparison as a general problem, they will establish a domain-independent foundation for the field that facilitates the design of future tools which allow the creation of more effective and scalable comparisons. To these ends the team will pursue three interconnected research threads. They will define theories that are grounded upon principles of visual cognition. They will explore case studies (derived from real problems suggested by domain collaborators) that challenge and extend these theories, provide examples for empirical study, and suggest or use general concepts. And they will identify common tasks, designs, and strategies that enable development of generalized techniques, guidelines, and software components. This approach uniquely combines empirical studies, design explorations, and software development to take the field of visual comparisons to a new level that is both rooted in theory yet viable in practice.
Broader Impacts: Because visual comparison plays a key role in diverse domains (including essentially all of the sciences, engineering, and medicine), the potential benefits from an improved science of visual comparison tools are far reaching. To ensure maximum applicability for project outcomes, the PIs are directly collaborating with physical, biological, social, educational, and medical scientists, as well as with engineers and scholars in the humanities. The project will generate visualization tools, software components, and resources for visualization development by others. Visual comparison will serve as a mechanism to expose students at all levels to issues in data understanding. This project will also provide training for visualization specialists, engage non-technical students in visualization, and explore the role of visualization in public outreach efforts.
