The World Magnetic Model and Associated Software
This site provides access to the DoD software and current WMM model and WMM online calculator. The software computes the main components of the geomagnetic field and their annual changes. The programs are designed to be used in demand mode. The software is available as both C and Fortran source code. The model file, WMM.COF, is expected to reside in the same directory as the software. Note: The altitude is referenced to the World Geodetic System 1984 (WGS 84) ellipsoid. The new WMM software library provides functions to convert height above mean sea level (AMSL) to height above WGS 84. This option is enabled by default. This function requires the geoid file EGM9615.BIN to reside in the same directory as the new WMM software.
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Input And Output
The input parameters and valid entries are:
- Latitude -90.00 to +90.00 degrees
Longitude -180.00 to +180.00 degrees
Altitude Sea level to 1,000,000 meters (referenced to the WGS 84 ellipsoid)
Date Base epoch of the current model to epoch + 5 years
The seven magnetic components computed are:
- F - Total Intensity of the geomagnetic field
H - Horizontal Intensity of the geomagnetic field
X - North Component of the geomagnetic field
Y - East Component of the geomagnetic field
Z - Vertical Component of the geomagnetic field
I (DIP) - Geomagnetic Inclination
D (DEC) - Geomagnetic Declination (Magnetic Variation)
Annual change in each of these magnetic components is also displayed. The annual
change is computed by subtracting the main field values for the desired input date
from main field values one year later. The output units are displayed using the
abbreviations nT (nanoTesla), deg (degrees) and min (minutes) per year.
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Online Calculator for the World Magnetic Model
DoD World Magnetic Model on-line calculator (2010 - 2015)
Note: Online calculators will switch from WMM2005 to WMM2010 on 1/1/2010
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Third party software for World Magnetic Model
Third party software is available here. Note: Neither the authors nor
NGDC can provide any warranty or technical support for these programs.
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Changes made to the WMM Code
As changes are made to the WMM code, the revised code will be posted.
Check this site for change notices.The download code will always be the latest version
Date
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Product
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Short description of changes
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Feb 4, 2010
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GUI now uses the new WMM subroutines. More information
on the updates is available in the software package. |
Dec 15, 2009
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GUI updated with the new WMM2010 coefficients. |
July 27, 2007
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WMM GUI is released |
Feb 4, 2010
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Version 1.0 is released. Extensive revision of the sublibrary, point, grid and file processing
programs. More information on the updates is available in the software package. |
Dec 15, 2009
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Version 0.3 is released. Software is updated with WMM2010 coefficients. |
Nov 17, 2009
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Beta version is released. |
Feb 4, 2010
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Version 3 is released. This is the last update for
this software. Floating point precision changed from single to double. More information
on the updates is available in the software package. |
Nov 5, 2005
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Version 2 is released. Changes include:
Spelling corrections in help text and input prompts,
Warnings added for undefined declination at / near magnetic poles,
Resolution of results consistent across all programs and
Corrected elevation bug in the Fortran grid program |
Apr 5, 2005
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C Software bug fixes: 1) Fixed inclination reporting (erroniously reported as positive upwards)
2) Fixed problem reading input which led to a memory leak and program fail when compiled with gnu compilers |
Dec 15, 2004
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Changes: As of 2000, the model produced and distributed from the
Web has been named "wmm.cof", with the model epoch contained in the header of the model.
The current model has an additional change to be compliant with Y2K. The publication date
of the model, as shown in the first line (header) of the model is now a four-digit year.
There are no changes in the format of the coefficients. |
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Download the World Magnetic Model - WMM2010 - software and documentation.
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