/* magfield.h -- compute local magnetic variation given position, ** altitude, and date ** ** This is an implementation of the NIMA WMM 2000 ** ** http://www.nima.mil/GandG/ngdc-wmm2000.html ** For WMM2000 coefficients: ** ftp://ftp.ngdc.noaa.gov/Solid_Earth/Mainfld_Mag/DoD_Model/wmm.cof ** For IGRF/DGRF coefficients: ** http://swdcdb.kugi.kyoto-u.ac.jp/igrf/coef/igrfall.d ** ** Copyright (C) 2000 Edward A Williams ** ** Adapted from Excel 3.0 version 3/27/94 EAW ** Recoded in C++ by Starry Chan ** WMM95 added and rearranged in ANSI-C EAW 7/9/95 ** Put shell around program and made Borland & GCC compatible EAW 11/22/95 ** IGRF95 added 2/96 EAW ** WMM2000 IGR2000 added 2/00 EAW ** Released under GPL 3/26/00 EAW ** Adaptions and modifications for the SimGear project 3/27/2000 CLO ** ** This program is free software; you can redistribute it and/or ** modify it under the terms of the GNU General Public License as ** published by the Free Software Foundation; either version 2 of the ** License, or (at your option) any later version. ** ** This program is distributed in the hope that it will be useful, but ** WITHOUT ANY WARRANTY; without even the implied warranty of ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ** General Public License for more details. ** ** You should have received a copy of the GNU General Public License ** along with this program; if not, write to the Free Software ** Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. ** */ #ifndef MAGFIELD_H #define MAGFIELD_H #ifdef __cplusplus extern "C" { /* extern "C" */ #endif /* Convert date to Julian day 1950-2049 */ unsigned long int yymmdd_to_julian_days( int yy, int mm, int dd ); /* Convert degrees to radians */ double deg_to_rad( double deg ); /* Convert radians to degrees */ double rad_to_deg( double rad ); /* return variation (in radians) given geodetic latitude (radians), longitude (radians) ,height (km), (Julian) date and field model model=1 is IGRF90, 2 is WMM85, 3 is WMM90, 4 is WMM95, 5 is IGRF95, 6 is WMM2000, 7 is IGRF2000 N and E lat and long are positive, S and W negative */ double SGMagVar( double lat, double lon, double h, long dat, int model, double* field ); #ifdef __cplusplus } /* extern "C" */ #endif #endif