Three-dimensional visualization involves the use of modern graphics hardware to present spatial data in three dimensions and allow the user to interact with the data in real time. When applied to geographic applications, this enables the user to view map data that include height information in a more intuitive and comprehensible form, rather than using a projection of those data onto a 2D plane. For example, Figure 1 illustrates a terrain elevation model that is displayed as a 3D surface, with satellite imagery mapped onto that surface and 3D building models overlaid on the terrain. The user is then free to view the scene from any vantage point or create a fly-through of the scene where a path is navigated through the 3D world.

A GIS ...