#ifndef lint
static const char SCCSID[]="@(#)PJ_lagrng.c 4.1 94/02/15 GIE REL";
#endif
#define PROJ_PARMS__ \
double hrw; \
double rw; \
double a1;
#define TOL 1e-10
#define PJ_LIB__
#include <projects.h>
PROJ_HEAD(lagrng, "Lagrange") "\n\tMisc Sph, no inv.\n\tW=";
FORWARD(s_forward); /* spheroid */
double v, c;
if (fabs(fabs(lp.phi) - HALFPI) < TOL) {
xy.x = 0;
xy.y = lp.phi < 0 ? -2. : 2.;
} else {
lp.phi = sin(lp.phi);
v = P->a1 * pow((1. + lp.phi)/(1. - lp.phi), P->hrw);
if ((c = 0.5 * (v + 1./v) + cos(lp.lam *= P->rw)) < TOL)
F_ERROR;
xy.x = 2. * sin(lp.lam) / c;
xy.y = (v - 1./v) / c;
}
return (xy);
}
FREEUP; if (P) pj_dalloc(P); }
ENTRY0(lagrng)
double phi1;
if ((P->rw = pj_param(P->params, "dW").f) <= 0) E_ERROR(-27);
P->hrw = 0.5 * (P->rw = 1. / P->rw);
phi1 = pj_param(P->params, "rlat_1").f;
if (fabs(fabs(phi1 = sin(phi1)) - 1.) < TOL) E_ERROR(-22);
P->a1 = pow((1. - phi1)/(1. + phi1), P->hrw);
P->es = 0.; P->fwd = s_forward;
ENDENTRY(P)
