Source code provided by NOAA into the public domain for estimating geomagnetic fields based on geolocation. This repo provides an easy way to build and test this code for educational and research purposes.

• GeomagnetismLibrary.c WMM Subroutine library, C functions
• GeomagnetismHeader.h WMM Subroutine library, C header file

• wmm_point.c Command prompt version for single point computation
• wmm_grid.c Grid, profile and time series computation, C main function
• wmm_file.c C program which takes a coordinate file as input with WMM ISO formatted coefficients as input

• WMM.COF WMM Coefficients file

• Geomagnetism_Library_Software_Manual.pdf Technical documents of the WMM Model and softwares

• wmm_point Command Prompt program for single point
• wmm_grid Grid, time series or profile
• wmm_file File processing

• WMM2015v2testvalues.pdf Test values for WMM2015
• sample_input_file.txt Sample input file for program wmm_file.exe
• sample_output_file.txt Sample output file for program wmmfile.exe

There is a Makefile in the source directory for building with gcc gcc -lm inputfile [dependencies] -o outputfile For example, the wmm_cmd.c can be compiled as gcc -lm wmm_cmd.c GeomagnetismLibrary.c -o wmm_cmd.exe Note: The library files GeomagnetismLibrary.c and GeomagnetismHeader.h should reside in the same directory for compiling.

• An experimental cmakefile is provided by this repo.

The file processing program accepts this syntax: wmm_file.exe f INPUT_FILE.txt OUTPUT_FILE.txt

Additionally to have uncertainty values appended to the output file add the "e" flag or "Errors". For example: wmm_file.exe f e INPUT_FILE.txt OUTPUT_FILE.txt

or

wmm_file.exe f --Errors INPUT_FILE.txt OUTPUT_FILE.txt

• National Centers for Environmental Information (NCEI)
• E/NE42 325 Broadway
• Boulder, CO 80303 USA
• Attn: Manoj Nair or Arnaud Chulliat
• Phone: (303) 497-4642 or -6522
• Email: [email protected] For more details about the World Magnetic Model visit http://www.ngdc.noaa.gov/geomag/WMM/DoDWMM.shtml