View size and pointing difficulty in multi-scale navigation

Using a new taxonomy of pointing tasks which includes view pointing beside traditional cursor pointing, we introduce the concept of multi-scale pointing. Analyzing the impact of view size, we demonstrate theoretically and experimentally that (1) the time needed to reach a remotely located target in a multi-scale interface still obeys Fitts' law and (2) the bandwidth of the interaction (i.e., the inverse of Fitts' law slope) is proportional to view size, a relationship bounded by an early ceiling effect. We discuss these results with special reference to navigation in miniaturized and enlarged interfaces.