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# define HLFPI2 2.46740110027233965467 /* (pi/2)^2 */
# define EPS 1e-10
#define PJ_LIB__
#include <errno.h>
#include <projects.h>
struct pj_opaque {
int bacn;
int ortl;
};
PROJ_HEAD(apian, "Apian Globular I") "\n\tMisc Sph, no inv.";
PROJ_HEAD(ortel, "Ortelius Oval") "\n\tMisc Sph, no inv.";
PROJ_HEAD(bacon, "Bacon Globular") "\n\tMisc Sph, no inv.";
static XY s_forward (LP lp, PJ *P) { /* Spheroidal, forward */
XY xy = {0.0,0.0};
struct pj_opaque *Q = P->opaque;
double ax, f;
xy.y = Q->bacn ? M_HALFPI * sin(lp.phi) : lp.phi;
if ((ax = fabs(lp.lam)) >= EPS) {
if (Q->ortl && ax >= M_HALFPI)
xy.x = sqrt(HLFPI2 - lp.phi * lp.phi + EPS) + ax - M_HALFPI;
else {
f = 0.5 * (HLFPI2 / ax + ax);
xy.x = ax - f + sqrt(f * f - xy.y * xy.y);
}
if (lp.lam < 0.) xy.x = - xy.x;
} else
xy.x = 0.;
return (xy);
}
PJ *PROJECTION(bacon) {
struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
if (0==Q)
return pj_default_destructor (P, ENOMEM);
P->opaque = Q;
Q->bacn = 1;
Q->ortl = 0;
P->es = 0.;
P->fwd = s_forward;
return P;
}
PJ *PROJECTION(apian) {
struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
if (0==Q)
return pj_default_destructor (P, ENOMEM);
P->opaque = Q;
Q->bacn = Q->ortl = 0;
P->es = 0.;
P->fwd = s_forward;
return P;
}
PJ *PROJECTION(ortel) {
struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
if (0==Q)
return pj_default_destructor (P, ENOMEM);
P->opaque = Q;
Q->bacn = 0;
Q->ortl = 1;
P->es = 0.;
P->fwd = s_forward;
return P;
}
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