ISG - International Service for the Geoid
ISG has been founded in 1992 (as International Geoid Service - IGeS) as a working arm of International Geoid Commission (IGeC), and it is actually an official Service of the International Association of Geodesy (IAG). ISG's activities are on educational, research, and data distribution sides: principal purposes of ISG are the collection and distribution of geoid models, the collection and distribution of software for geoid computation, and the organization of technical schools on geoid determinations.