The application and research of spatial information are generally considered as a challenging problem due to the excessive voluminousness

complexity of processing and difficulty in sharing of spatial data. As a novel web-based infrastructure and technology system of spatial information

Spatial Information Grid （SIG） integrates and extends information grid technology

spatial information system

web services and etc. To implement sharing and integration of spatial information

SIG takes service as its technical core

and establishes a unified and intelligent platform to acquire store

organize

distrbute

analyze

aggregate

and apply

spatial information. Based on the given basic definitions of SIG

the technical ingredients and research contents are proposed. Then

a system architecture of SIG is proposed and built. Moreover

some key technologise

of SIG

such as spatial data sharing and spatial analyzing services are studied and elaborated. Hences

the system framework and technical foundation of SIG are formed and SIG research is promoted into a new stage.