The world is becomingly increasingly data rich, and our abilities to make good decisions in all realms - from personal to policy - rests on our abilities to analyze and convey data in meaningful ways. Unfortunately, human beings are limited in our perceptual and cognitive abilities, making it difficult for us to use these large amounts of data. Data visualization holds promise as one mechanism for making sense of and presenting large amounts of data in a way that reduces information overload, and supports comprehension, memory, and decision-making.