int IGRFCall(double date, double flat, double flon,
double elev, double *x, double *y, double *z) {
int i;
char *envstr;
char file1[256];
char file2[256];
double ext[3]={0.0,0.0,0.0};
double a2 = 40680925.0;
double b2 = 40408588.0;
if (igrf_date !=date) {
for (i=0;(dtemod[i] !=0) && (dtemod[i]<date);i++);
if (i==0) return -1;
i--;
igrf_date=date;
envstr=getenv("IGRF_PATH");
sprintf(file1,"%s/%s",envstr,filmod[i]);
getshc(file1, &nmax1, &erad, gh1);
sprintf(file2,"%s/%s",envstr,filmod[i+1]);
getshc(file2, &nmax2, &erad, gh2);
if (i < 12) {
interpshc(date, dtemod[i],
nmax1, gh1, dtemod[i+1], nmax2, gh2, &nmax, gha);
interpshc(date+1,dtemod[i],
nmax1, gh1, dtemod[i+1], nmax2, gh2, &nmax, ghb);
} else {
extrapshc(date, dtemod[i],
nmax1, gh1, nmax2, gh2, &nmax, gha);
extrapshc(date+1,dtemod[i],
nmax1, gh1, nmax2, gh2, &nmax, ghb);
}
}
shval3(1, flat, flon, elev, erad, a2, b2, nmax, gha, 0,
ext, x, y, z);
return 0;
}
int main () {
double inArray[MAXCOEFF];
for (int i=1; i<=MAXCOEFF; i++) {
inArray[i] = i;
}
pointCoords loc;
loc.lat = 0;
loc.lon = 0;
loc.elev = 0;
shval3(
loc,
10,
&inArray[0],
3, 10.0, 10.0, 10.0);
return 0;
}
int IGRFCall(double date, double flat, double flon,
double elev, double *x, double *y, double *z) {
int i;
char *envstr;
char file1[256];
char file2[256];
char line[256];
FILE *fp;
double ext[3]={0.0,0.0,0.0};
double a2 = 40680925.0;
double b2 = 40408588.0;
if (dtemax==0) {
envstr=getenv("IGRF_PATH");
sprintf(file1,"%s/%s",envstr,"coef.dat");
fp=fopen(file1,"r");
if (fp==NULL) return -1;
int i=0;
while (fgets(line,255,fp) !=NULL) {
sscanf(line,"%s %lf",filmod[i],&dtemod[i]);
i++;
}
dtemod[i]=0;
dtemax=i-2;
fclose(fp);
}
if (igrf_date !=date) {
for (i=0;(dtemod[i] !=0) && (dtemod[i]<date);i++);
if (i==0) return -1;
i--;
igrf_date=date;
envstr=getenv("IGRF_PATH");
sprintf(file1,"%s/%s",envstr,filmod[i]);
getshc(file1, &nmax1, &erad, gh1);
sprintf(file2,"%s/%s",envstr,filmod[i+1]);
getshc(file2, &nmax2, &erad, gh2);
if (i < dtemax) {
interpshc(date, dtemod[i],
nmax1, gh1, dtemod[i+1], nmax2, gh2, &nmax, gha);
interpshc(date+1,dtemod[i],
nmax1, gh1, dtemod[i+1], nmax2, gh2, &nmax, ghb);
} else {
extrapshc(date, dtemod[i],
nmax1, gh1, nmax2, gh2, &nmax, gha);
extrapshc(date+1,dtemod[i],
nmax1, gh1, nmax2, gh2, &nmax, ghb);
}
}
shval3(2, flat, flon, elev, erad, a2, b2, nmax, gha, 0,
ext, x, y, z);
return 0;
}
void geomag(geomag_vector *gStr) {
/* Variable declaration */
double sdate = gStr->sdate;
double latitude = gStr->latitude;
double longitude = gStr->longitude;
double alt = gStr->alt;
/* Control variables */
uint8_t igdgc = 2; /* GEOCENTRIC */
static int max1;
static int max2;
static int max3;
static int nmax;
static uint8_t model[] = "IGRF2015";
static double epoch;
static double yrmin;
static double yrmax;
static double minyr;
static double maxyr;
static double altmin;
static double altmax;
static double minalt;
static double maxalt;
/* Obtain the desired model file and read the data */
if (PREV_SDATE == 0) {
epoch = 2015.00;
max1 = 13;
max2 = 8;
max3 = 0;
yrmin = 2015.00;
yrmax = 2020.00;
altmin = -1.0;
altmax = 600.0;
minyr = yrmin;
maxyr = yrmax;
}
PREV_SDATE = sdate;
/* Get altitude min and max for selected model. */
minalt = altmin;
maxalt = altmax;
/* Get Coordinate prefs */
/* If needed modify ranges to reflect coords. */
if (igdgc == 2) {
minalt += 6371.2; /* Add radius to ranges. */
maxalt += 6371.2;
}
/** This will compute everything needed for 1 point in time. **/
getshc(1, max1, 1);
getshc(0, max2, 2);
nmax = extrapsh(sdate, epoch, max1, max2, 3);
nmax = extrapsh(sdate + 1, epoch, max1, max2, 4);
/* Do the first calculations */
shval3(igdgc, latitude, longitude, alt, nmax, 3, IEXT, EXT_COEFF1,
EXT_COEFF2,
EXT_COEFF3);
dihf(3);
shval3(igdgc, latitude, longitude, alt, nmax, 4, IEXT, EXT_COEFF1,
EXT_COEFF2,
EXT_COEFF3);
dihf(4);
d = d * (RAD2DEG);
i = i * (RAD2DEG);
/* deal with geographic and magnetic poles */
/* at magnetic poles */
if (h < 100.0) {
d = GEO_NAN;
/* while rest is ok */
}
/* at geographic poles */
if (90.0 - fabs(latitude) <= 0.001) {
x = GEO_NAN;
y = GEO_NAN;
d = GEO_NAN;
/* while rest is ok */
}
/** Above will compute everything for 1 point in time. **/
gStr->Xm = x;
gStr->Ym = y;
gStr->Zm = z;
gStr->decl = d;
gStr->incl = i;
gStr->h = h;
gStr->f = f;
}
