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#define PJ_LIB__
#include <errno.h>
#include <math.h>
#include "proj.h"
#include "proj_internal.h"
PROJ_HEAD(imw_p, "International Map of the World Polyconic")
"\n\tMod. Polyconic, Ell\n\tlat_1= and lat_2= [lon_1=]";
#define TOL 1e-10
#define EPS 1e-10
namespace { // anonymous namespace
enum Mode {
NONE_IS_ZERO = 0, /* phi_1 and phi_2 != 0 */
PHI_1_IS_ZERO = 1, /* phi_1 = 0 */
PHI_2_IS_ZERO = -1 /* phi_2 = 0 */
};
} // anonymous namespace
namespace { // anonymous namespace
struct pj_opaque {
double P, Pp, Q, Qp, R_1, R_2, sphi_1, sphi_2, C2;
double phi_1, phi_2, lam_1;
double *en;
enum Mode mode;
};
} // anonymous namespace
static int phi12(PJ *P, double *del, double *sig) {
struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
int err = 0;
if (!pj_param(P->ctx, P->params, "tlat_1").i ||
!pj_param(P->ctx, P->params, "tlat_2").i) {
err = PJD_ERR_LAT_1_2_UNSPECIFIED;
} else {
Q->phi_1 = pj_param(P->ctx, P->params, "rlat_1").f;
Q->phi_2 = pj_param(P->ctx, P->params, "rlat_2").f;
*del = 0.5 * (Q->phi_2 - Q->phi_1);
*sig = 0.5 * (Q->phi_2 + Q->phi_1);
err = (fabs(*del) < EPS || fabs(*sig) < EPS) ? PJD_ERR_ABS_LAT1_EQ_ABS_LAT2 : 0;
}
return err;
}
static PJ_XY loc_for(PJ_LP lp, PJ *P, double *yc) {
struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
PJ_XY xy;
if (lp.phi == 0.0) {
xy.x = lp.lam;
xy.y = 0.;
} else {
double xa, ya, xb, yb, xc, D, B, m, sp, t, R, C;
sp = sin(lp.phi);
m = pj_mlfn(lp.phi, sp, cos(lp.phi), Q->en);
xa = Q->Pp + Q->Qp * m;
ya = Q->P + Q->Q * m;
R = 1. / (tan(lp.phi) * sqrt(1. - P->es * sp * sp));
C = sqrt(R * R - xa * xa);
if (lp.phi < 0.) C = - C;
C += ya - R;
if (Q->mode == PHI_2_IS_ZERO) {
xb = lp.lam;
yb = Q->C2;
} else {
t = lp.lam * Q->sphi_2;
xb = Q->R_2 * sin(t);
yb = Q->C2 + Q->R_2 * (1. - cos(t));
}
if (Q->mode == PHI_1_IS_ZERO) {
xc = lp.lam;
*yc = 0.;
} else {
t = lp.lam * Q->sphi_1;
xc = Q->R_1 * sin(t);
*yc = Q->R_1 * (1. - cos(t));
}
D = (xb - xc)/(yb - *yc);
B = xc + D * (C + R - *yc);
xy.x = D * sqrt(R * R * (1 + D * D) - B * B);
if (lp.phi > 0)
xy.x = - xy.x;
xy.x = (B + xy.x) / (1. + D * D);
xy.y = sqrt(R * R - xy.x * xy.x);
if (lp.phi > 0)
xy.y = - xy.y;
xy.y += C + R;
}
return xy;
}
static PJ_XY imw_p_e_forward (PJ_LP lp, PJ *P) { /* Ellipsoidal, forward */
double yc;
PJ_XY xy = loc_for(lp, P, &yc);
return (xy);
}
static PJ_LP imw_p_e_inverse (PJ_XY xy, PJ *P) { /* Ellipsoidal, inverse */
PJ_LP lp = {0.0,0.0};
struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
PJ_XY t;
double yc = 0.0;
int i = 0;
const int N_MAX_ITER = 1000; /* Arbitrarily chosen number... */
lp.phi = Q->phi_2;
lp.lam = xy.x / cos(lp.phi);
do {
t = loc_for(lp, P, &yc);
const double denom = t.y - yc;
if( denom != 0 || fabs(t.y - xy.y) > TOL )
{
if( denom == 0 ) {
proj_errno_set(P, PJD_ERR_NON_CONVERGENT);
return proj_coord_error().lp;
}
lp.phi = ((lp.phi - Q->phi_1) * (xy.y - yc) / denom) + Q->phi_1;
}
if( t.x != 0 && fabs(t.x - xy.x) > TOL )
lp.lam = lp.lam * xy.x / t.x;
i ++;
} while (i < N_MAX_ITER &&
(fabs(t.x - xy.x) > TOL || fabs(t.y - xy.y) > TOL));
if( i == N_MAX_ITER )
{
proj_errno_set(P, PJD_ERR_NON_CONVERGENT);
return proj_coord_error().lp;
}
return lp;
}
static void xy(PJ *P, double phi, double *x, double *y, double *sp, double *R) {
double F;
*sp = sin(phi);
*R = 1./(tan(phi) * sqrt(1. - P->es * *sp * *sp ));
F = static_cast<struct pj_opaque*>(P->opaque)->lam_1 * *sp;
*y = *R * (1 - cos(F));
*x = *R * sin(F);
}
static PJ *destructor (PJ *P, int errlev) {
if (nullptr==P)
return nullptr;
if (nullptr==P->opaque)
return pj_default_destructor (P, errlev);
if( static_cast<struct pj_opaque*>(P->opaque)->en )
pj_dealloc (static_cast<struct pj_opaque*>(P->opaque)->en);
return pj_default_destructor(P, errlev);
}
PJ *PROJECTION(imw_p) {
double del, sig, s, t, x1, x2, T2, y1, m1, m2, y2;
int err;
struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
if (nullptr==Q)
return pj_default_destructor (P, ENOMEM);
P->opaque = Q;
if (!(Q->en = pj_enfn(P->es))) return pj_default_destructor (P, ENOMEM);
if( (err = phi12(P, &del, &sig)) != 0) {
return destructor(P, err);
}
if (Q->phi_2 < Q->phi_1) { /* make sure P->phi_1 most southerly */
del = Q->phi_1;
Q->phi_1 = Q->phi_2;
Q->phi_2 = del;
}
if (pj_param(P->ctx, P->params, "tlon_1").i)
Q->lam_1 = pj_param(P->ctx, P->params, "rlon_1").f;
else { /* use predefined based upon latitude */
sig = fabs(sig * RAD_TO_DEG);
if (sig <= 60) sig = 2.;
else if (sig <= 76) sig = 4.;
else sig = 8.;
Q->lam_1 = sig * DEG_TO_RAD;
}
Q->mode = NONE_IS_ZERO;
if (Q->phi_1 != 0.0)
xy(P, Q->phi_1, &x1, &y1, &Q->sphi_1, &Q->R_1);
else {
Q->mode = PHI_1_IS_ZERO;
y1 = 0.;
x1 = Q->lam_1;
}
if (Q->phi_2 != 0.0)
xy(P, Q->phi_2, &x2, &T2, &Q->sphi_2, &Q->R_2);
else {
Q->mode = PHI_2_IS_ZERO;
T2 = 0.;
x2 = Q->lam_1;
}
m1 = pj_mlfn(Q->phi_1, Q->sphi_1, cos(Q->phi_1), Q->en);
m2 = pj_mlfn(Q->phi_2, Q->sphi_2, cos(Q->phi_2), Q->en);
t = m2 - m1;
s = x2 - x1;
y2 = sqrt(t * t - s * s) + y1;
Q->C2 = y2 - T2;
t = 1. / t;
Q->P = (m2 * y1 - m1 * y2) * t;
Q->Q = (y2 - y1) * t;
Q->Pp = (m2 * x1 - m1 * x2) * t;
Q->Qp = (x2 - x1) * t;
P->fwd = imw_p_e_forward;
P->inv = imw_p_e_inverse;
P->destructor = destructor;
return P;
}
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