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Geomagnetism is one of the oldest geophysical sciences. Geomagnetic fields have been observed and used since ancient times, and are still used for modern applications in 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.

World Magnetic Model Annual Report

Access Tools


A mobile app with a digital compass that can calculate the magnetic field in your area.

Geomagnetic Calculators

Geomagnetic Calculators can be used to measure different aspects of the magnetic field for specific time frames and coordinates.

Historic Declination Map Viewer

This map displays historical isogonic lines and magnetic poles calculated for the years 1590–2025.