Application: gvSIG desktop

#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)