The International Center for Global Earth Models collects and distributes historical and actual global gravity
field models of the Earth and offers calculation service for derived quantities. In particular the tasks include: collecting and archiving of all existing global gravity field models, web interface for getting access to global gravity field models, web based visualization of the gravity field models their differences and their time variation, web based service for calculating different functionals of the gravity field models, web site for tutorials on spherical harmonics and the theory of the calculation service. As new service since 2016, ICGEM is providing a Digital Object Identifier (DOI) for the data set of the model (the coefficients).
ICGEM is one of six centres of the International Gravity Field Service (IGFS) of the International Association of Geodesy (IAG).
The other five Centres are
Bureau Gravimetrique International (BGI) at CNES / CRGS, Toulouse, France
Digital Elevation Model Centre (DEM) at Montfort University, UK
International Centre for Earth Tides (ICET) at University of French Polynesia
International Geoid Service (IGeS) at Politecnico di Milano, Milan, Italy
Technical Support Centre of IGFS at NGA, Saint Louis, USA