/**
* @brief Performs actual photometric correction calculations
*
* This routine computes photometric correction using parameters
* for the Hillier-Buratti-Hill equation.
*
* @author Kris Becker - 2/21/2010
*
* @param parms Container of band-specific Hillier parameters
* @param i Incidence angle in degrees
* @param e Emission angle in degrees
* @param g Phase angle in degrees
*
* @return double Photometric correction parameter
*/
double Hillier::photometry(const Parameters &parms, double i, double e,
double g) const {
// Ensure problematic values are adjusted
if(i == 0.0) i = 10.E-12;
if(e == 0.0) e = 10.E-12;
// Convert to radians
i *= rpd_c();
e *= rpd_c();
g *= parms.phaUnit; // Apply unit normalizer
// Compute Lommel-Seeliger components
double mu = cos(e);
double mu0 = cos(i);
double alpha = g;
double alpha2 = g * g;
// Simple Hillier photometric polynomial equation with exponential opposition
// surge term.
double rcal = (mu0 / (mu + mu0)) * (parms.b0 * exp(-parms.b1 * alpha) + parms.a0 +
(parms.a1 * alpha) + (parms.a2 * alpha2) +
(parms.a3 * alpha * alpha2) +
(parms.a4 * alpha2 * alpha2));
return (rcal);
}
int main (int argc, char **argv) {
SpiceDouble lt;
SpiceDouble ang;
SpiceDouble v[3];
SpiceDouble pos[3];
int i;
furnsh_c("/home/barrycarter/BCGIT/ASTRO/standard.tm");
// spkezp_c(299,0,"ITRF93","LT+S",399,v,<);
// printf("POS: %f,%f,%f\n",v[0],v[1],v[2]);
// exit(0);
// abq roughly
georec_c (-106.5*rpd_c(), 35.05*rpd_c(), 1.609344, 6378.137,
(6378.137-6356.7523)/6378.137, pos);
for (i=0; i<=86400; i+=3600) {
// pos of sun from IAU_EARTH
spkezp_c(10,i,"ITRF93","LT+S",399,v,<);
printf("POS(%d): %f,%f,%f\n",i,v[0],v[1],v[2]);
// angle between abq vector and sun vector (0 = zenith)
ang = vsep_c (v,pos);
// printf("%d %f\n",i,r2d(ang));
}
return 0;
}
int main(void) {
furnsh_c("/home/barrycarter/BCGIT/ASTRO/standard.tm");
double stime = 1448953200, etime = 1454310000;
double lat, lon, dl, noon, mindl, minnoon;
for (lat = 22.; lat<=67.; lat+=1.) {
for (lon = -74.; lon <= -71.; lon+=0.1) {
double *results = bcriset(lat*rpd_c(),lon*rpd_c(), 0, stime, etime,
"Sun", -5/6.*rpd_c(), ">");
mindl = 0.;
minnoon = 0.;
// we intentionally ignore first result, expect it to be wrong
// TODO: this assumption is invalid, and, even if it were valid,
// should be i=1, not i=2
for (int i=2; i<=100; i++) {
// if we start seeing 0s, we are out of true answers
if (results[2*i] < .001) {break;}
// if the end result is too close to etime, result is inaccurate
if (abs(results[2*i+1]-etime)<1) {continue;}
// length of day and "noon"
dl = results[2*i+1]-results[2*i];
noon = (results[2*i+1]+results[2*i])/2;
// if day length is less than mindl (or mindl = 0), set mindl and
// minnoon to current
if (mindl < .01 || dl < mindl) {
mindl = dl;
minnoon = noon;
}
}
// the start of December for this longitude (1448928000 = GMT
// midnight Dec 1)
double sod = 1448928000-240.*lon;
// this is: minimal time of noon and length of day
printf("%f %f %f %f %f\n", lat, lon, minnoon, mindl,
1+(minnoon-sod)/86400);
}
}
return 0;
}
/**
* @brief Extracts necessary Hillier parameters from profile
*
* Given a profile read from the input PVL file, this method
* extracts needed parameters (from Keywords) in the PVL profile
* and creates a container of the converted values.
*
* @author Kris Becker - 2/22/2010
*
* @param p Profile to extract/convert
*
* @return Hillier::Parameters Container of extracted values
*/
Hillier::Parameters Hillier::extract(const DbProfile &p) const {
Parameters pars;
pars.b0 = toDouble(ConfKey(p, "B0", toString(0.0)));
pars.b1 = toDouble(ConfKey(p, "B1", toString(0.0)));
pars.a0 = toDouble(ConfKey(p, "A0", toString(0.0)));
pars.a1 = toDouble(ConfKey(p, "A1", toString(0.0)));
pars.a2 = toDouble(ConfKey(p, "A2", toString(0.0)));
pars.a3 = toDouble(ConfKey(p, "A3", toString(0.0)));
pars.a4 = toDouble(ConfKey(p, "A4", toString(0.0)));
pars.wavelength = toDouble(ConfKey(p, "BandBinCenter", toString(Null)));
pars.tolerance = toDouble(ConfKey(p, "BandBinCenterTolerance", toString(Null)));
// Determine equation units - defaults to Radians
pars.units = ConfKey(p, "HillierUnits", QString("Radians"));
pars.phaUnit = (pars.units.toLower() == "degrees") ? 1.0 : rpd_c();
return (pars);
}
static VALUE rpd(VALUE self) {
return DBL2NUM(rpd_c());
}
