EVOLUTION-MANAGER

Edit File: pj_phi2.c

/* determine latitude angle phi-2 */ #include <projects.h> #define HALFPI 1.5707963267948966 #define TOL 1.0e-10 #define N_ITER 15 double pj_phi2(projCtx ctx, double ts, double e) { double eccnth, Phi, con, dphi; int i; eccnth = .5 * e; Phi = HALFPI - 2. * atan (ts); i = N_ITER; do { con = e * sin (Phi); dphi = HALFPI - 2. * atan (ts * pow((1. - con) / (1. + con), eccnth)) - Phi; Phi += dphi; } while ( fabs(dphi) > TOL && --i); if (i <= 0) pj_ctx_set_errno( ctx, -18 ); return Phi; }