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, power grid operations, and communications in aviation and defence.
We connect customer software to geomagnetic data via our web APIs. Visit our self-service Developer Portal for a 14 day free trial. Subscriptions start from $120 per month covered by a Service Level Agreement.
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 (variation), inclination, and intensity at a particular time and position. It is relied upon throughout the world for navigation, mineral exploration, atmospheric and space science. Access WMM via our web API.
The Ap geomagnetism index is used to measure the overall level of space weather induced geomagnetic activity on Earth. It is derived from the Kp index, which quantifies disturbances in the Earth's magnetic field caused by solar wind and other solar activities. Such disturbances can impact:
Power grid operators — strong geomagnetic storms induce currents in transmission lines, potentially damaging transformers (Québec blackout, 1989).
Aviation & spaceflight — Ap correlates with radiation risk and communication/navigation disruptions for aircraft and astronauts.
Military & defense — dependent on radar, communications, and navigation systems that can be degraded.
The official values for the Ap index, along with other related geomagnetic activity indices such as the three-hour Kp index, are calculated by the GeoForschungsZentrum Helmholtz Centre in Potsdam, Germany. Access geomagnetic indices via our web API.
Not fluent in RESTful web APIs and JSON and programming languages used for magnetic declination compass corrections?
No problem, we make geomagnetic data accessible to the masses by connecting our APIs with the LLM tools people already use, like ChatGPT!
This enables natural language requests for simple data lookups or corrections. For example:
“Using the Amentum Geomag API, show me the magnetic declination in Brisbane, Australia, today.” or
“Pull the total field intensity for 40°N, 75°W at altitude of 400 km from last week.”