The World Magnetic Model (WMM) is the standard model for navigation, attitude, and heading referencing systems that use the geomagnetic field. WMM is produced by the United States’ National Geospatial-Intelligence Agency (NGA) and the United Kingdom’s Defence Geographic Centre (DGC). CIRES/NCEI and the British Geological Survey (BGS) jointly developed the WMM. This interactive tool visualizes World Magnetic Model (WMM) errors as a function of altitude and geomagnetic activity.
Quick Start: Select G-scale → Pick component → Adjust altitude → View map. Click anywhere for details.
Altitudes: 0–10,000 km
Geomagnetic Storm Levels: G0–G5 (uses real-time Kp index data)
Field Components: F, D, I, H, X, Y, and Z
Understanding the Error Thresholds:
- MilSpec – The U.S. Department of Defense Military Specification (MIL-PRF-89500B) defines the maximum acceptable RMS error thresholds that the WMM must meet throughout its 5-year operational lifespan. These represent upper bounds on acceptable discrepancy between the model and the true geomagnetic field.
- WMM Error Model – A more stringent, data-driven estimate of the WMM's expected accuracy in practice, as documented in the WMM2025 Technical Report. This threshold reflects the model's actual performance based on commission and omission error analysis.
Learn More
Nair, M., Fillion, M., Chulliat, A., & Califf, S. (2025). Global geomagnetic model errors as a function of altitude and geomagnetic activity. Space Weather, 23(10), e2025SW004579. View paper ↗
Nair, M., Chulliat, A., Fillion, M., & Califf, S. (2025). Model-based error grids and satellite-derived errors for the world magnetic model (WMM) [Dataset]. Zenodo. Download data ↗