The Earth's magnetic field is generated by electric currents in the molten outer core, and affected by local variations in the mantle and crust. Above the surface, fluctuations of magnetospheric and ionospheric origin are increasingly significant and are impacted by the solar wind. The magnetic field protects us from cosmic radiation and the atmosphere from erosion by the solar wind. Understanding geomagnetic fields is critical to compass navigation. The direction of magnetic north does not correspond to the geographic north, and a correction (magnetic declination or variation) is required to convert from one to the other. The direction of the magnetic field vector varies with position and time (the Earth's magnetic poles shift over time). Scientists around the world are studying this variation to improve our understanding of it, and ability to predict changes. The World Magnetic Model (WMM) is scientific software that calculates magnetic declination, inclination, and intensity at a particular time and position. It is based on data measured by dedicated satellites as part of the SWARM mission and by the ground based observatories of the INTERMAGNET network. It is relied upon throughout the world for navigation, mineral exploration, atmospheric and space science, and is installed on billions of devices in some form. Accessing the model programmatically from modern software can be difficult and time consuming. Our API provides geomagnetic declination and other properties for a given date and location using a standard interface. Integration is achieved in minutes. Let us know here (or via our website) if you have any questions, feedback, or need help getting started.

Amentum Geomag API

Geomagnetic data at your fingertips!

Geomagnetic data at your fingertips!