/Proj4/PJ_collg.c
C | 32 lines | 32 code | 0 blank | 0 comment | 6 complexity | a03681b22b038800402f19827eaa81b4 MD5 | raw file
1#ifndef lint 2static const char SCCSID[]="@(#)PJ_collg.c 4.1 94/02/15 GIE REL"; 3#endif 4#define PJ_LIB__ 5# include "projects.h" 6PROJ_HEAD(collg, "Collignon") "\n\tPCyl, Sph."; 7#define FXC 1.12837916709551257390 8#define FYC 1.77245385090551602729 9#define ONEEPS 1.0000001 10FORWARD(s_forward); /* spheroid */ 11 if ((xy.y = 1. - sin(lp.phi)) <= 0.) 12 xy.y = 0.; 13 else 14 xy.y = sqrt(xy.y); 15 xy.x = FXC * lp.lam * xy.y; 16 xy.y = FYC * (1. - xy.y); 17 return (xy); 18} 19INVERSE(s_inverse); /* spheroid */ 20 lp.phi = xy.y / FYC - 1.; 21 if (fabs(lp.phi = 1. - lp.phi * lp.phi) < 1.) 22 lp.phi = asin(lp.phi); 23 else if (fabs(lp.phi) > ONEEPS) I_ERROR 24 else lp.phi = lp.phi < 0. ? -HALFPI : HALFPI; 25 if ((lp.lam = 1. - sin(lp.phi)) <= 0.) 26 lp.lam = 0.; 27 else 28 lp.lam = xy.x / (FXC * sqrt(lp.lam)); 29 return (lp); 30} 31FREEUP; if (P) pj_dalloc(P); } 32ENTRY0(collg) P->es = 0.; P->inv = s_inverse; P->fwd = s_forward; ENDENTRY(P)