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 NOAA > NESDIS > NCEI (formerly NGDC) > Geomagnetism

EMAG2, background image © GFZ Potsdan 1999

What's New?

new High Def Geomagnetic Model (HDGM2019)
new EMM 2017
new Earth Magnetic Anomaly Model (EMAG2)

Models are joint research with:

The Cooperative Institute for Research in Environmental Sciences (CIRES).


The study of geomagnetism is one of the oldest of the geophysical sciences. The geomagnetic fields have been observed and used from ancient times. Modern uses of geomagnetic data include navigation and mineral exploration. The National Centers for Environmental Information develops and distributes models of the geomagnetic field and maintains archives of geomagnetic data to further the understanding of Earth magnetism and the Sun-Earth environment.

Online Calculators

Declination Grid Calculation Magnetic Field US Historic Declination

NOAA has updated the magnetic calculator(s). The older style calculators will continue to be available for a limited time through the CIRES Geomagnetism site. Access the backup calculators.

Geomagnetic Models & Software

new Earth Magnetic Anomaly Model (EMAG2) new Enhanced Magnetic Model (EMM)
Intl Geomagnetic Reference Field (IGRF)
World Magnetic Model (WMM) Maps and Images (ftp)
High Definition Geomagnetic Model (HDGM) Historic Declination Mapviewer 

Geomagnetic Data

Indices Paleomagnetic
Marine Magnetic


Geomagnetism Poster Geomagnetism Tri-Fold
WMM Handout Geomagnetism Impact Handout
Geomagnetic Services Handout CrowdMag project
Geomagnetism story map by ESRI ( External site disclaimer )

Trackline (marine and airborne) data and derived geomagnetic models and software are managed by NCEI and collocated World Data Center for Geophysics.

map and north arrow
Declination Calculator

World Magnetic Model (WMM) declination
World Magnetic Model

Enhanced Magnetic Model (EMM)
Enhanced Magnetic Model

Earth Magnetic Anomaly Model (EMAG2)
Earth Magnetic Anomaly Model (EMAG2)