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#define PJ_LIB__
#include <errno.h>
#include <math.h>
#include "proj.h"
#include "projects.h"
#include "proj_math.h"
struct pj_opaque {
double phi1;
double phi2;
double n;
double rho;
double rho0;
double c;
double *en;
int ellips;
};
PROJ_HEAD(eqdc, "Equidistant Conic")
"\n\tConic, Sph&Ell\n\tlat_1= lat_2=";
# define EPS10 1.e-10
static XY e_forward (LP lp, PJ *P) { /* Ellipsoidal, forward */
XY xy = {0.0,0.0};
struct pj_opaque *Q = P->opaque;
Q->rho = Q->c - (Q->ellips ? pj_mlfn(lp.phi, sin(lp.phi),
cos(lp.phi), Q->en) : lp.phi);
xy.x = Q->rho * sin( lp.lam *= Q->n );
xy.y = Q->rho0 - Q->rho * cos(lp.lam);
return xy;
}
static LP e_inverse (XY xy, PJ *P) { /* Ellipsoidal, inverse */
LP lp = {0.0,0.0};
struct pj_opaque *Q = P->opaque;
if ((Q->rho = hypot(xy.x, xy.y = Q->rho0 - xy.y)) != 0.0 ) {
if (Q->n < 0.) {
Q->rho = -Q->rho;
xy.x = -xy.x;
xy.y = -xy.y;
}
lp.phi = Q->c - Q->rho;
if (Q->ellips)
lp.phi = pj_inv_mlfn(P->ctx, lp.phi, P->es, Q->en);
lp.lam = atan2(xy.x, xy.y) / Q->n;
} else {
lp.lam = 0.;
lp.phi = Q->n > 0. ? M_HALFPI : -M_HALFPI;
}
return lp;
}
static void *destructor (PJ *P, int errlev) { /* Destructor */
if (0==P)
return 0;
if (0==P->opaque)
return pj_default_destructor (P, errlev);
pj_dealloc (P->opaque->en);
return pj_default_destructor (P, errlev);
}
PJ *PROJECTION(eqdc) {
double cosphi, sinphi;
int secant;
struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
if (0==Q)
return pj_default_destructor (P, ENOMEM);
P->opaque = Q;
P->destructor = destructor;
Q->phi1 = pj_param(P->ctx, P->params, "rlat_1").f;
Q->phi2 = pj_param(P->ctx, P->params, "rlat_2").f;
if (fabs(Q->phi1 + Q->phi2) < EPS10)
return pj_default_destructor (P, PJD_ERR_CONIC_LAT_EQUAL);
if (!(Q->en = pj_enfn(P->es)))
return pj_default_destructor(P, ENOMEM);
Q->n = sinphi = sin(Q->phi1);
cosphi = cos(Q->phi1);
secant = fabs(Q->phi1 - Q->phi2) >= EPS10;
if( (Q->ellips = (P->es > 0.)) ) {
double ml1, m1;
m1 = pj_msfn(sinphi, cosphi, P->es);
ml1 = pj_mlfn(Q->phi1, sinphi, cosphi, Q->en);
if (secant) { /* secant cone */
sinphi = sin(Q->phi2);
cosphi = cos(Q->phi2);
Q->n = (m1 - pj_msfn(sinphi, cosphi, P->es)) /
(pj_mlfn(Q->phi2, sinphi, cosphi, Q->en) - ml1);
}
Q->c = ml1 + m1 / Q->n;
Q->rho0 = Q->c - pj_mlfn(P->phi0, sin(P->phi0),
cos(P->phi0), Q->en);
} else {
if (secant)
Q->n = (cosphi - cos(Q->phi2)) / (Q->phi2 - Q->phi1);
Q->c = Q->phi1 + cos(Q->phi1) / Q->n;
Q->rho0 = Q->c - P->phi0;
}
P->inv = e_inverse;
P->fwd = e_forward;
return P;
}
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