Revised version with new title, "Navigation Patterns and Usability of Zoomable User Interfaces with and without an Overview", ACM Transactions on Computer-Human Interaction, Vol. 9, No. 4, pp. 362-389, December 2002.
HCIL-2001-11, CS-TR-4267, UMIACS-TR-2001-48
The literature on information visualizations establishes the usability of overview+detail interfaces, but for zoomable user interfaces, results are mixed. We compare overview+detail and zoomable user interfaces to understand the navigation patterns and usability of these interfaces. Thirty-two subjects solved navigation and browsing tasks on maps organized in one or multiple levels. We find no difference between interfaces in subjects' ability to solve tasks correctly. Eighty percent of the subjects prefer the overview+detail interface, stating that it supports navigation and helps keep track of their position on the map. However, subjects are faster using the zoomable user interface, especially in combination with the multi-level map and when solving navigation tasks. The combination of the zoomable user interface and the multi-level map also improves subjects' recall of objects on the map. Switching between overview and detail windows was correlated with higher task completion time, suggesting that integration of overview and detail windows require mental and motor effort. We found large individual differences in navigation patterns and usability, but subjects' visualization ability influenced usability similarly between interfaces.