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NOAA > NESDIS > NCEI (formerly NGDC) > Geomagnetism

EMAG2, background image © GFZ Potsdan 1999

What's New?

new High Def Geomagnetic Model (HDGM2023)
new WMM Annual Report in 2021

Models are joint research with:

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

This website is being retired. Please check out our new website here


The study of geomagnetism is one of the oldest of the geophysical sciences. Geomagnetic fields have been observed and used since ancient times. Modern uses of geomagnetic data include navigation and mineral exploration. NCEI 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 calculators, including the Enhanced Magnetic Model calculator, an attractive mobile compass app and ESRI location search tool. All new and existing users of the geomagnetic calculator APIs must register and obtain a key.

Geomagnetic Models & Software

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

Geomagnetic Data

Airborne Marine Magnetic
Indices Paleomagnetic


Earth's Magnetic Field: The Force That's Always with You - ESRI Story Map
Geomagnetism Poster Geomagnetism Brochure
Geomagnetic Services Handout Geomagnetism Impact Handout
WMM Handout CrowdMag

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)