The Internet and other advances in technology have dramatically affected cartography in recent decades and yet these new capabilities have not been adequately evaluated for effectiveness. Are dynamic maps more effective than traditional static paper maps in allowing users to visualize spatio-temporal patterns? How important is a higher level of interactivity in visualizing data? Which format is preferred? To examine these questions, human subject tests were conducted to evaluate different levels of interactivity as represented by 1) a static paper map series; 2) an animated map with 'VCR'-type controls; and 3) a toggle map featuring an interactive temporal legend. Results indicate that while the level of interactivity did not affect accuracy of answers to questions regarding spatio-temporal patterns, the total amount of time in which these questions were answered lessened as the level of interactivity increased. Overall, test subjects were more enthusiastic towards the tools featuring greater interactivity.