Previous research on the Virtual Geographic Environment(VGE) has focused mainly on representation rather than geographic analysis.However,geographic analysis plays a significant role in modern geography.To address this issue,this paper systematically examines theories and implementing VGE techniques that support geographical analysis and simulation.Based on its framework,VGE can be divided into four subtypes.These are the data environment,modeling environment,expression environment,and collaborative environment.The functions and key techniques of each are examined,and some case studies are discussed.This study provides direction for necessary new developments of advanced VGE platforms.
