World Magnetic Model function declarations

Collaboration diagram for World Magnetic Model function declarations:

Functions
int32_t	geomag_front (gvector pos, double year, rvector &comp)

Detailed Description

Function Documentation

int32_t geomag_front	(	gvector	pos,
		double	time,
		rvector &	comp
	)

Main function to compute the magnetic field from the World Magnetic Model

Input: Position, time | output: Mag Field

Parameters

pos	geodetic position (lon, lat, alt) in (rad, rad, meters)
time	in decimal year, ex. use mjd2year(currentmjd())
comp	are the magnetic field x,y,z components in Topocentric System

{
    static int maxdeg, itime;
    static float alt,  dec, dip, ti, gv, bx, by, bz;

    // this reads the coefficients, specify path if neccessary
    itime = 5 * (int)(time/5.);
    string rname;
    int32_t iretn = get_cosmosresources(rname);
    if (iretn < 0)
    {
        return iretn;
    }
    sprintf(fname, "%s/general/wmm_%04d.cof", rname.c_str(), itime);

    /* INITIALIZE GEOMAG ROUTINE */


    maxdeg = 12;
    //  warn_H = 0;
    //  warn_H_val = 99999.0;
    //  warn_H_strong = 0;
    //  warn_H_strong_val = 99999.0;
    //  warn_P = 0;

    if (!initialized)
    {
        iretn = geomag(&maxdeg);
        if (iretn < 0)
        {
            return iretn;
        }
        initialized = 1;
    }


    // convert alt to km
    alt = (float)(pos.h/1000.);
    // !!! add comment/description to each filed
    iretn = geomg1(alt, // altitude in km
                   (float)pos.lat, // lattitude in rad?
                   (float)pos.lon, // longitude in rad?
                   (float)time, // time in decimal year
                   &dec,
                   &dip,
                   &ti,
                   &gv,
                   &bx,
                   &by,
                   &bz);
    if (iretn < 0)
    {
        return iretn;
    }
    //      time = time1 + 1.0;


    /*COMPUTE X, Y, Z, AND H COMPONENTS OF THE MAGNETIC FIELD*/
    //  ti *= 1e-9;
    //  comp->col[0] = ti*(cos(dec)*cos(dip));
    //  comp->col[1] = ti*(cos(dip)*sin(dec));
    //  comp->col[2] = ti*(sin(dip));
    comp.col[0] = static_cast <double>(bx * 1e-9f);
    comp.col[1] = static_cast <double>(by * 1e-9f);
    comp.col[2] = static_cast <double>(bz * 1e-9f);

    /*
    if (length_rv(lcomp) != 0. && lcomp.col[0] != comp->col[0] && lcomp.col[1] != comp->col[1] &&lcomp.col[2] != comp->col[2])
    {
        dcomp = rv_smult(1./(time-ltime),rv_sub(*comp,lcomp));
        lperiod = .001*length_rv(*comp)/length_rv(dcomp);
    }
    ltime = time;
    lcomp = *comp;
    */
    return 0;
}