AGU - American Geophysical Union home page.
Canadian Institute of Geomatics (CIG)
CoAxial Research Page (GIS and the deep ocean floor)
Friends of the Earth
CIESIN - The Consortium for International Earth Science Information Network.
GEOWorld, Inc.
Institute for Space and Terrestrial Science (CAN).
International Map Trade Association
OpenGIS Consortium, Inc. GIS Interoperability through OGIS
The Association for Geographic Information
URISA International Homepage
Welcome to the AGI GIS Dictionary

Canadian Association of Geographers 

Geobase

Centre for Spatial Database Management & Solutions (CSDMS)

California Geographic Information Association

AAG

ASPRS
GeoData Alliance

GIS International Group (GISIG)

GRASS GIS News

Herring Run Watershed Association

inovaGIS

IACA

LISA

National Caving Association (UK)

NACIS

Spatial Technologies Industry Association

SRMIS (Canada)

UNIGISInternational