Navigational techniques to improve the display of large two-dimensional spaces

Abstract Often the components of a problem can be arrayed on a two-dimensional information space—for example, as an abstract tree or hypertext—far too large to fit onto a computer display. With current navigational techniques it is often difficult for users to keep track of their location or to move rapidly to remote locations in the space. We implemented two similar direct-manipulation techniques, both of which use a map window—a miniature of the entire information space—with a wire-frame box to aid users in remembering their location. The first technique allows the user to rapidly roam over the information space by moving the location of the wire-frame box. The second allows for zooming as well as roaming. A controlled experiment compared the above techniques to scroll bars for determining whether a target word was in a large balanced binary tree of words. The experiment also examined the merit of the map window. Map windows significantly improved user performance, and the roam and zoom techniques were found to be significantly faster than the scroll bars. Our observation of subjects and their verbal protocol indicated that a paging feature on the scroll bars—allowing rapid movement of the screen a page in any direction—was advantageous.