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#define PROJ_PARMS__ \
double w; \
double m, rm;
#define PJ_LIB__
#define EPS 1.0e-10
# include <projects.h>
PROJ_HEAD(hammer, "Hammer & Eckert-Greifendorff")
"\n\tMisc Sph, \n\tW= M=";
FORWARD(s_forward); /* spheroid */
double cosphi, d;
d = sqrt(2./(1. + (cosphi = cos(lp.phi)) * cos(lp.lam *= P->w)));
xy.x = P->m * d * cosphi * sin(lp.lam);
xy.y = P->rm * d * sin(lp.phi);
return (xy);
}
INVERSE(s_inverse); /* spheroid */
double z;
z = sqrt(1. - 0.25*P->w*P->w*xy.x*xy.x - 0.25*xy.y*xy.y);
if (fabs(2.*z*z-1.) < EPS) {
lp.lam = HUGE_VAL;
lp.phi = HUGE_VAL;
pj_errno = -14;
} else {
lp.lam = aatan2(P->w * xy.x * z,2. * z * z - 1)/P->w;
lp.phi = aasin(P->ctx,z * xy.y);
}
return (lp);
}
FREEUP; if (P) pj_dalloc(P); }
ENTRY0(hammer)
if (pj_param(P->ctx, P->params, "tW").i) {
if ((P->w = fabs(pj_param(P->ctx, P->params, "dW").f)) <= 0.) E_ERROR(-27);
} else
P->w = .5;
if (pj_param(P->ctx, P->params, "tM").i) {
if ((P->m = fabs(pj_param(P->ctx, P->params, "dM").f)) <= 0.) E_ERROR(-27);
} else
P->m = 1.;
P->rm = 1. / P->m;
P->m /= P->w;
P->es = 0.; P->fwd = s_forward; P->inv = s_inverse;
ENDENTRY(P)
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