NOAA > NCEI (formerly NGDC) > Geomagnetic Data & Info > HDGM Home

Geomagnetic Declination

HDGM provides higher resolution magnetic directional (or pointing) information than standard models. An example from Caspian sea.

Click to Enlarge

Real-Time Magnetic Disturbance

HDGM-RT is able to correct for disturbances caused by large geomagnetic storms.

Click to Enlarge








What's new in HDGM-2017

- Main field and secular variation update valid until December 31, 2018, using over 3 years of Swarm data
- 2015-2016 models retroactively updated with new Swarm data
- HDGM-RT includes a new model of the ionospheric field, in addition to the magnetospheric model!

Contact us for a quote

What is HDGM

The High Definition Geomagnetic Model (HDGM) is a global, high resolution model of the Earth's geomagnetic main and crustal field, providing magnetic field values (total field, dip, and declination) at any point above or below the Earth's surface. Well planners can use HDGM to compute magnetic reference values at any point, as well as easily integrate HDGM into their directional drilling software. HDGM is updated annually to correctly model secular changes in the geomagnetic field. More Information

What is HDGM-RT

The Real Time add-on to the High Definition Geomagnetic Model (HDGM-RT) includes a model of Earth's external disturbance field which provides near real-time estimates of magnetic effects from current systems in the magnetosphere and ionosphere. It is based on near real-time ground observatory measurements of magnetospheric fields as well as solar wind observations from satellites. HDGM-RT includes all of the features available within the HDGM, plus access to the real-time magnetospheric and ionospheric field models. More Information

IGRF vs HDGM vs HDGM-RT

Compare Model FeaturesIGRFHDGMHDGM-RT
Average secular variation (5-year)
Rapid secular variation (1-year) 
133 km crustal resolution (satellite) 
28 km crustal resolution
(airborne/marine surveys)
 
Annually averaged disturbance field 
Real-time disturbance field  
Ionospheric field