Design of 3D Models for 3D GIS

In traditional planar maps,we use symbols to represent spatial objects.With the development of computer technique and 3D techniques and their application in GIS,traditional 2D static planar map is developed to 3D dynamic virtual environment.CyberCity is a hotspot in the field of GIS and it needs not only by DEM and 3D terrain to deliver the topographic information,but also 3D symbol models to represent spatial objects.Representation of CyberCity is not reconstruction in all details,but based on the abstraction and interpretation of real world according to the temporal-spatial,economic and technical constraints.So it is necessary to study on the 3D model.This paper discusses the transmission pattern of spatial information,the difference and relations between map symbols and 3D models,then illustrates the principles of 3D models based on their determinability,location,simplification and logicality.