In theory, 3D scene is more suitable to the human
perception of the real environment, so it’s more effective in
representation of spatial information than 2D map. As a lot of
assumptions based on instinct are not always right, it is
indiscreet to draw the conclusion that 3D visualization is better
than 2D symbolized graphics in spatial knowledge acquisition
and spatial memory only because 3D visualization can express
realistic space phenomena. In fact, 3D visualization is
attractive and is applied increasingly in different industries, so
a lot of experiments have been done on comparison of people's
spatial cognitive efficiency in 2D and 3D environment. From
results of these experiments, many of the conclusions are
contradictory, and sometimes the conclusions are completely
different from experiments on the same subject and make by
the same author [Cockburn et al, 2001].