As a next generation geographic analysis tool

Virtual Geographic Environments（ VGEs） have remarkable predominance in enhancing human cognition of the geographic world and in solving geographic problems. Most studies currently focused on VGE structures and technologies. However

research productions on basic theory

such as geographic semantics and data representation models

are few. In particular

the weakness of VGE cognitive theory has restrained the further development of VGEs. VGE cognition attempts to improve the usability

efficiency

equity

and profitability of VGEs with geo-knowledge obtained through the synthesized research of human geographic cognition rules

as well as the VGE nature and building methods. This research provides not only an effective guide to VGE construction but also theoretical and methodological guidance to the geographic cognition

geographic analysis

and modeling of remote sensing information. This article reviews several understandings of VGEs and suggests that cognition research on VGEs should be derived from the perspective of system theory to contribute to the future scientific development of VGEs. From this perspective

VGEs are complex systems of human environments

virtual environments created by computers

and realistic environments. The differences between the cognition of VGEs and other similar concepts are discussed to draw their clear boundaries. Geographic and map cognition are important bases of VGE cognition

but developing a new cognitive research framework of VGEs in reference to VGE characteristics are necessary. Thus

a cognitive research framework is developed from similarities that include thinking

perception

geometry

characteristic

and discreteness similarities in both realistic and virtual environments. Thinking similarity is the emphasis and the difficulty of VGE cognitive research. It is also the basis of building VGEs that are consistent with human cognition. The course of human cognition is through image schema

category

conception

and meaning. Thus

thinking similarity should include the specialization of human cognition models on geographic environments

context model building of VGEs

computer model of geographic concepts

and formalization and contextualized representation of geographic models. Perception similarity is an important factor in generating immersion and is a key to distinguishing VGEs and other spatial cognition tools. Thus

the multi-modal interaction

dynamic representation adaptability

cognitive load

and work efficiency experimentation of VGEs should be studied. VGEs should balance realistic representation and non-realistic representation

which is called realistic representation adaptability to geometry similarity. Given the multi-scale characteristic and scale dependence of both the geographic process and study method

characteristic similarity should include multiple-scale adaptability and representation of formalization models. VGE uncertainty is produced when discrete geographic data are translated into a continuous spatialtime process representation

which is lacking in VGE research. Based on the above framework

VGE cognitive research is placed in its wider context. The function of the geographic experiment platform of VGEs and human function in VGEs is also emphasized.This study has a large significance in deepening VGE research.