Esempio n. 1
0
        // general inverse projection
        // inverse projection entry
        public static LP pj_inv(XY xy, PJ P)
        {
            LP lp;

            // can't do as much preliminary checking as with forward
            if(xy.x==Libc.HUGE_VAL||xy.y==Libc.HUGE_VAL)
            {
                lp.lam=lp.phi=Libc.HUGE_VAL;
                pj_ctx_set_errno(P.ctx, -15);

                return lp;
            }

            Libc.errno=pj_errno=0;
            P.ctx.last_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); // inverse project
            if(P.ctx.last_errno!=0)
            {
                lp.lam=lp.phi=Libc.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&&Math.Abs(Math.Abs(lp.phi)-HALFPI)>EPS12)
                    lp.phi=Math.Atan(P.one_es*Math.Tan(lp.phi));
            }

            return lp;
        }