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#define PJ_LIB__
#include <errno.h>
#include <proj.h>
#include "projects.h"
PROJ_HEAD(urm5, "Urmaev V") "\n\tPCyl., Sph., no inv.\n\tn= q= alpha=";
struct pj_opaque {
double m, rmn, q3, n;
};
static XY s_forward (LP lp, PJ *P) { /* Spheroidal, forward */
XY xy = {0.0, 0.0};
struct pj_opaque *Q = P->opaque;
double t;
t = lp.phi = aasin (P->ctx, Q->n * sin (lp.phi));
xy.x = Q->m * lp.lam * cos (lp.phi);
t *= t;
xy.y = lp.phi * (1. + t * Q->q3) * Q->rmn;
return xy;
}
PJ *PROJECTION(urm5) {
double alpha, t;
struct pj_opaque *Q = pj_calloc (1, sizeof (struct pj_opaque));
if (0==Q)
return pj_default_destructor(P, ENOMEM);
P->opaque = Q;
if (pj_param(P->ctx, P->params, "tn").i) {
Q->n = pj_param(P->ctx, P->params, "dn").f;
if (Q->n <= 0. || Q->n > 1.)
return pj_default_destructor(P, PJD_ERR_N_OUT_OF_RANGE);
} else {
return pj_default_destructor(P, PJD_ERR_N_OUT_OF_RANGE);
}
Q->q3 = pj_param(P->ctx, P->params, "dq").f / 3.;
alpha = pj_param(P->ctx, P->params, "ralpha").f;
t = Q->n * sin (alpha);
Q->m = cos (alpha) / sqrt (1. - t * t);
Q->rmn = 1. / (Q->m * Q->n);
P->es = 0.;
P->inv = 0;
P->fwd = s_forward;
return P;
}
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