Based on the theory of map information transmission, the
categorical rule and drafting law are researched and a principle
of establishing a 3D symbol is presented in this paper, which
contains two aspects The one is that all kinds of spatial feature
information which are suitable for description by 3D symbol
models have been identified, the other is that it should be
implemented at the viewpoint of computer graphics and
visualization. And the basic concept of 3D map symbol model