A useful thread in exploring panning and zooming is the concept of the zooming user interface (ZUI). Demos of this are especially valuable because they give a detailed view of the power of panning and zooming for navigating an online environment that integrates text and pictures. An elegant example of this is illustrated in the demo from the Raskin Center, shown in the screen-shots below.
Note here in the intro screen (above) that it’s so easy to see where pictures and text are that the large print labels (Pictures, Documents) are really unnecessary. After getting used to the idea that small chunks of text can quickly be zoomed to a readable size, it’s easy to move around the environment. From the intro screen, the Human Interface box is zoomed to the the size below.
The second and third screen-shots (above and below) especially show the power of this sort of interface to integrate pictures and text — The tiny “thumbnail” picture of the Amazon.com page in the screen-shot above zooms to the full-sized page in the screen-shot below.
An interesting sidelight to this narrative is that the Raskin Center, where this demo resides, was founded by Jef Raskin, who launched the Macintosh Project, and is often called the “Father of the Macintosh.”
For more – WikiPedia : Zooming user interface has good links to examples of ZUI’s.