HDGM2027

HDGM continues with Monarch.

HDGM2027 is the next annual release of the High Definition Geomagnetic Model. Existing coefficient-file and software workflows will continue with minimal disruption, making the transition straightforward for current users.

Request licensing information What's new in HDGM2027

Continuity

What carries forward with HDGM2027.

An established product lineage, longstanding scientific leadership, and familiar workflows continue through the transition.

Product & scientific continuity

HDGM has supported directional-drilling workflows across the industry for many years. Monarch co-founders Arnaud Chulliat and Manoj C. Nair have led the development of HDGM for more than a decade and will continue its scientific development at Monarch.

Workflow & transition continuity

Monarch Magnetics will provide HDGM going forward under a license from the University of Colorado. HDGM2027 will retain the existing coefficient-file format and the established DLL and console application workflows. The web API will provide the same HDGM evaluation functionality from Monarch's cloud infrastructure.

Existing integrations in well-planning and other operational software can therefore move to HDGM2027 without changing the underlying HDGM workflow. Licensing and support will be provided directly by Monarch.

Transition overlap: HDGM2027 releases November 1, 2026; NOAA continues supporting current users through December 31, 2026.

NOAA/NCEI HDGM product page NOAA/NESDIS Notice of Changes

HDGM-RT continuity

HDGM2027 + SWC-Global

SWC-Global is Monarch's global time-varying correction and the continuation path for the external-field functionality provided by HDGM-RT. Combined with HDGM2027, it carries that functionality forward within Monarch's product architecture.

Explore time-varying correction

The reference field

A high-resolution global reference for magnetic surveying.

HDGM combines Earth's main magnetic field and its secular variation with a high-resolution crustal-field model and an average external field. The result provides spatial detail beyond the Low Resolution Geomagnetic Model (LRGM) category used in directional-drilling workflows.

That additional detail matters where magnetic-field accuracy contributes directly to wellbore-positioning accuracy.

Side-by-side magnetic declination maps over the Permian Basin comparing IGRF and HDGM on a shared color scale, with HDGM showing finer spatial structure. — **Permian Basin example.** Magnetic declination across the same 30 × 30 km region at 2.50 km MSL, epoch 2026.0, comparing IGRF and HDGM on a shared color scale. IGRF represents the Low Resolution Geomagnetic Model (LRGM) category; HDGM is a High Resolution Geomagnetic Model (HRGM). Data underlying the crustal-field modeling include U.S. Geological Survey (USGS) magnetic observations and broader international geomagnetic datasets.

HDGM2027

What is improving in HDGM2027.

HDGM2027 advances the spatial description of the crustal field and adds location-specific uncertainty information.

Improved crustal-field modeling

HDGM2027 includes a higher-resolution crustal-field model that represents shorter-wavelength magnetic structure.

Location-specific uncertainty

HDGM2027 will provide uncertainty information that varies with location, giving users a more useful description of model confidence for operational applications.

Global map illustrating geographic variation in relative field-strength uncertainty, with dark stippling indicating sparse survey coverage. — **Illustrative** relative field-strength uncertainty. Lighter shading indicates lower relative uncertainty, while dark stippling indicates sparse survey coverage.

Access & support

Familiar product interfaces, now supported by Monarch.

HDGM2027 will continue to be available through model coefficient files, the DLL, console application, and web API. Monarch will provide licensing, technical support, and access to each annual HDGM release.

Files

Model coefficients

The HDGM coefficient-file format remains unchanged for compatibility with existing implementations.

Software

DLL & console application

The DLL and console application will continue with the established interfaces used for embedded and batch workflows.

Service

Web API

The web API will continue to provide HDGM field evaluations from Monarch's cloud infrastructure.

The geomagnetic stack

HDGM provides the reference-field foundation.

HDGM provides the reference field, IFR1 adds local crustal refinement, and IFR2 accounts for time-varying changes in the magnetic field.

HDGMReference field IFR1Local crustal refinement IFR2Time-varying correction

Uncertainty + validation across the stack

HDGM2027 licensing

Planning for the 2027 model year?

Contact Monarch for HDGM2027 licensing information, transition questions, or technical support for your existing HDGM workflow.

Contact Monarch contact@monarchmag.com

Monarch Magnetics Boulder, Colorado, USA