Application: gvSIG desktop

/* general inverse projection */

#ifndef lint

static const char SCCSID[]="@(#)pj_inv.c        4.5        93/06/12        GIE        REL";

#endif

#define PJ_LIB__

#include <projects.h>

#include <errno.h>

# define EPS 1.0e-12

        LP /* inverse projection entry */

pj_inv(XY xy, PJ *P) {

        LP lp;

        /* can't do as much preliminary checking as with forward */

        if (xy.x == HUGE_VAL || xy.y == HUGE_VAL) {

                lp.lam = lp.phi = HUGE_VAL;

                pj_errno = -15;

        }

        errno = pj_errno = 0;

        xy.x = (xy.x * P->to_meter - P->x0) * P->ra; /* descale and de-offset */

        xy.y = (xy.y * P->to_meter - P->y0) * P->ra;

        lp = (*P->inv)(xy, P); /* inverse project */

        if (pj_errno || (pj_errno = errno))

                lp.lam = lp.phi = HUGE_VAL;

        else {

                lp.lam += P->lam0; /* reduce from del lp.lam */

                if (!P->over)

                        lp.lam = adjlon(lp.lam); /* adjust longitude to CM */

                if (P->geoc && fabs(fabs(lp.phi)-HALFPI) > EPS)

                        lp.phi = atan(P->one_es * tan(lp.phi));

        }

        return lp;

}