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#define PJ_LIB__
#include <errno.h>
#include "proj.h"
#include "projects.h"
#include "proj_math.h"
PROJ_HEAD(lcc, "Lambert Conformal Conic")
"\n\tConic, Sph&Ell\n\tlat_1= and lat_2= or lat_0, k_0=";
#define EPS10 1.e-10
struct pj_opaque {
double phi1;
double phi2;
double n;
double rho0;
double c;
};
static XY e_forward (LP lp, PJ *P) { /* Ellipsoidal, forward */
XY xy = {0., 0.};
struct pj_opaque *Q = P->opaque;
double rho;
if (fabs(fabs(lp.phi) - M_HALFPI) < EPS10) {
if ((lp.phi * Q->n) <= 0.) {
proj_errno_set(P, PJD_ERR_TOLERANCE_CONDITION);
return xy;
}
rho = 0.;
} else {
rho = Q->c * (P->es != 0. ?
pow(pj_tsfn(lp.phi, sin(lp.phi), P->e), Q->n) :
pow(tan(M_FORTPI + .5 * lp.phi), -Q->n));
}
lp.lam *= Q->n;
xy.x = P->k0 * (rho * sin(lp.lam));
xy.y = P->k0 * (Q->rho0 - rho * cos(lp.lam));
return xy;
}
static LP e_inverse (XY xy, PJ *P) { /* Ellipsoidal, inverse */
LP lp = {0., 0.};
struct pj_opaque *Q = P->opaque;
double rho;
xy.x /= P->k0;
xy.y /= P->k0;
xy.y = Q->rho0 - xy.y;
rho = hypot(xy.x, xy.y);
if (rho != 0.) {
if (Q->n < 0.) {
rho = -rho;
xy.x = -xy.x;
xy.y = -xy.y;
}
if (P->es != 0.) {
lp.phi = pj_phi2(P->ctx, pow(rho / Q->c, 1./Q->n), P->e);
if (lp.phi == HUGE_VAL) {
proj_errno_set(P, PJD_ERR_TOLERANCE_CONDITION);
return lp;
}
} else
lp.phi = 2. * atan(pow(Q->c / rho, 1./Q->n)) - M_HALFPI;
lp.lam = atan2(xy.x, xy.y) / Q->n;
} else {
lp.lam = 0.;
lp.phi = Q->n > 0. ? M_HALFPI : -M_HALFPI;
}
return lp;
}
PJ *PROJECTION(lcc) {
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;
Q->phi1 = pj_param(P->ctx, P->params, "rlat_1").f;
if (pj_param(P->ctx, P->params, "tlat_2").i)
Q->phi2 = pj_param(P->ctx, P->params, "rlat_2").f;
else {
Q->phi2 = Q->phi1;
if (!pj_param(P->ctx, P->params, "tlat_0").i)
P->phi0 = Q->phi1;
}
if (fabs(Q->phi1 + Q->phi2) < EPS10)
return pj_default_destructor(P, PJD_ERR_CONIC_LAT_EQUAL);
Q->n = sinphi = sin(Q->phi1);
cosphi = cos(Q->phi1);
secant = fabs(Q->phi1 - Q->phi2) >= EPS10;
if (P->es != 0.) {
double ml1, m1;
m1 = pj_msfn(sinphi, cosphi, P->es);
ml1 = pj_tsfn(Q->phi1, sinphi, P->e);
if (secant) { /* secant cone */
sinphi = sin(Q->phi2);
Q->n = log(m1 / pj_msfn(sinphi, cos(Q->phi2), P->es));
Q->n /= log(ml1 / pj_tsfn(Q->phi2, sinphi, P->e));
}
Q->c = (Q->rho0 = m1 * pow(ml1, -Q->n) / Q->n);
Q->rho0 *= (fabs(fabs(P->phi0) - M_HALFPI) < EPS10) ? 0. :
pow(pj_tsfn(P->phi0, sin(P->phi0), P->e), Q->n);
} else {
if (secant)
Q->n = log(cosphi / cos(Q->phi2)) /
log(tan(M_FORTPI + .5 * Q->phi2) /
tan(M_FORTPI + .5 * Q->phi1));
Q->c = cosphi * pow(tan(M_FORTPI + .5 * Q->phi1), Q->n) / Q->n;
Q->rho0 = (fabs(fabs(P->phi0) - M_HALFPI) < EPS10) ? 0. :
Q->c * pow(tan(M_FORTPI + .5 * P->phi0), -Q->n);
}
P->inv = e_inverse;
P->fwd = e_forward;
return P;
}
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