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/* general inverse projection */
#define PJ_LIB__
#include <projects.h>
#include <errno.h>
# define EPS 1.0e-12
/* inverse projection entry */
LP 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_ctx_set_errno( P->ctx, -15);
return lp;
}
errno = pj_errno = 0;
P->ctx->last_errno = 0;
/* descale and de-offset */
xy.x = (xy.x * P->to_meter - P->x0) * P->ra;
xy.y = (xy.y * P->to_meter - P->y0) * P->ra;
/* Check for NULL pointer */
if (P->inv != NULL) {
lp = (*P->inv)(xy, P); /* inverse project */
if (P->ctx->last_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)-M_HALFPI) > EPS)
lp.phi = atan(P->one_es * tan(lp.phi));
}
} else {
lp.lam = lp.phi = HUGE_VAL;
}
return lp;
}
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