Smooth generalization is the study of gradual changes on a map that are needed when the scale changes continuously on a screen. Scale changes can be due to user interaction (zoom in/out) or they can be in an animation. Ideas for smooth generalization are described in:

M. van Kreveld. Smooth generalization for continuous zooming. Paper. In Proc. 20th International Cartographic Conference, pages 2180--2185, 2001.

In a master thesis project, Tom Priester developed two applets that illustrate smooth generalization in an interactive environment. The first shows fading and appearing of roads during zooming, and the second shows simplification of moor boundaries. The applets contain a lot of controls for zooming and testing the generalization. A description of these can be found in Tom Priester's master's thesis.

Short instructions: left-click on the map to zoom in, right-click to zoom out. The middle mouse button is used for panning. Generalization changes may continue briefly after zooming stops.