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#define PJ_LIB__
#include <math.h>
#include "proj.h"
#include "proj_internal.h"
PROJ_HEAD(nicol, "Nicolosi Globular") "\n\tMisc Sph, no inv";
#define EPS 1e-10
static PJ_XY nicol_s_forward (PJ_LP lp, PJ *P) { /* Spheroidal, forward */
PJ_XY xy = {0.0,0.0};
(void) P;
if (fabs(lp.lam) < EPS) {
xy.x = 0;
xy.y = lp.phi;
} else if (fabs(lp.phi) < EPS) {
xy.x = lp.lam;
xy.y = 0.;
} else if (fabs(fabs(lp.lam) - M_HALFPI) < EPS) {
xy.x = lp.lam * cos(lp.phi);
xy.y = M_HALFPI * sin(lp.phi);
} else if (fabs(fabs(lp.phi) - M_HALFPI) < EPS) {
xy.x = 0;
xy.y = lp.phi;
} else {
double tb, c, d, m, n, r2, sp;
tb = M_HALFPI / lp.lam - lp.lam / M_HALFPI;
c = lp.phi / M_HALFPI;
d = (1 - c * c)/((sp = sin(lp.phi)) - c);
r2 = tb / d;
r2 *= r2;
m = (tb * sp / d - 0.5 * tb)/(1. + r2);
n = (sp / r2 + 0.5 * d)/(1. + 1./r2);
xy.x = cos(lp.phi);
xy.x = sqrt(m * m + xy.x * xy.x / (1. + r2));
xy.x = M_HALFPI * ( m + (lp.lam < 0. ? -xy.x : xy.x));
xy.y = sqrt(n * n - (sp * sp / r2 + d * sp - 1.) /
(1. + 1./r2));
xy.y = M_HALFPI * ( n + (lp.phi < 0. ? xy.y : -xy.y ));
}
return (xy);
}
PJ *PROJECTION(nicol) {
P->es = 0.;
P->fwd = nicol_s_forward;
return P;
}
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