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#define PJ_LIB__
#include <errno.h>
#include "proj.h"
#include "proj_internal.h"
#include <math.h>
PROJ_HEAD(oea, "Oblated Equal Area") "\n\tMisc Sph\n\tn= m= theta=";
namespace { // anonymous namespace
struct pj_opaque {
double theta;
double m, n;
double two_r_m, two_r_n, rm, rn, hm, hn;
double cp0, sp0;
};
} // anonymous namespace
static PJ_XY oea_s_forward (PJ_LP lp, PJ *P) { /* Spheroidal, forward */
PJ_XY xy = {0.0,0.0};
struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
const double cp = cos(lp.phi);
const double sp = sin(lp.phi);
const double cl = cos(lp.lam);
const double Az = aatan2(cp * sin(lp.lam), Q->cp0 * sp - Q->sp0 * cp * cl) + Q->theta;
const double shz = sin(0.5 * aacos(P->ctx, Q->sp0 * sp + Q->cp0 * cp * cl));
const double M = aasin(P->ctx, shz * sin(Az));
const double N = aasin(P->ctx, shz * cos(Az) * cos(M) / cos(M * Q->two_r_m));
xy.y = Q->n * sin(N * Q->two_r_n);
xy.x = Q->m * sin(M * Q->two_r_m) * cos(N) / cos(N * Q->two_r_n);
return xy;
}
static PJ_LP oea_s_inverse (PJ_XY xy, PJ *P) { /* Spheroidal, inverse */
PJ_LP lp = {0.0,0.0};
struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
const double N = Q->hn * aasin(P->ctx,xy.y * Q->rn);
const double M = Q->hm * aasin(P->ctx,xy.x * Q->rm * cos(N * Q->two_r_n) / cos(N));
const double xp = 2. * sin(M);
const double yp = 2. * sin(N) * cos(M * Q->two_r_m) / cos(M);
const double Az = aatan2(xp, yp) - Q->theta;
const double cAz = cos(Az);
const double z = 2. * aasin(P->ctx, 0.5 * hypot(xp, yp));
const double sz = sin(z);
const double cz = cos(z);
lp.phi = aasin(P->ctx, Q->sp0 * cz + Q->cp0 * sz * cAz);
lp.lam = aatan2(sz * sin(Az),
Q->cp0 * cz - Q->sp0 * sz * cAz);
return lp;
}
PJ *PROJECTION(oea) {
struct pj_opaque *Q = static_cast<struct pj_opaque*>(calloc (1, sizeof (struct pj_opaque)));
if (nullptr==Q)
return pj_default_destructor (P, PROJ_ERR_OTHER /*ENOMEM*/);
P->opaque = Q;
if (((Q->n = pj_param(P->ctx, P->params, "dn").f) <= 0.) )
{
proj_log_error(P, _("Invalid value for n: it should be > 0"));
return pj_default_destructor(P, PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE);
}
if (((Q->m = pj_param(P->ctx, P->params, "dm").f) <= 0.) )
{
proj_log_error(P, _("Invalid value for m: it should be > 0"));
return pj_default_destructor(P, PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE);
}
Q->theta = pj_param(P->ctx, P->params, "rtheta").f;
Q->sp0 = sin(P->phi0);
Q->cp0 = cos(P->phi0);
Q->rn = 1./ Q->n;
Q->rm = 1./ Q->m;
Q->two_r_n = 2. * Q->rn;
Q->two_r_m = 2. * Q->rm;
Q->hm = 0.5 * Q->m;
Q->hn = 0.5 * Q->n;
P->fwd = oea_s_forward;
P->inv = oea_s_inverse;
P->es = 0.;
return P;
}
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