Application: gvSIG desktop

#ifndef lint

static const char SCCSID[]="@(#)PJ_tcea.c        4.1        94/02/15        GIE        REL";

#endif

#define PROJ_PARMS__ \

        double rk0;

#define PJ_LIB__

#include        <projects.h>

PROJ_HEAD(tcea, "Transverse Cylindrical Equal Area") "\n\tCyl, Sph";

FORWARD(s_forward); /* spheroid */

        xy.x = P->rk0 * cos(lp.phi) * sin(lp.lam);

        xy.y = P->k0 * (atan2(tan(lp.phi), cos(lp.lam)) - P->phi0);

        return (xy);

}

INVERSE(s_inverse); /* spheroid */

        double t;

        xy.y = xy.y * P->rk0 + P->phi0;

        xy.x *= P->k0;

        t = sqrt(1. - xy.x * xy.x);

        lp.phi = asin(t * sin(xy.y));

        lp.lam = atan2(xy.x, t * cos(xy.y));

        return (lp);

}

FREEUP; if (P) pj_dalloc(P); }

ENTRY0(tcea)

        P->rk0 = 1 / P->k0;

        P->inv = s_inverse;

        P->fwd = s_forward;

        P->es = 0.;

ENDENTRY(P)