/Proj4/PJ_collg.c
http://github.com/route-me/route-me · C · 32 lines · 32 code · 0 blank · 0 comment · 6 complexity · a03681b22b038800402f19827eaa81b4 MD5 · raw file
- #ifndef lint
- static const char SCCSID[]="@(#)PJ_collg.c 4.1 94/02/15 GIE REL";
- #endif
- #define PJ_LIB__
- # include "projects.h"
- PROJ_HEAD(collg, "Collignon") "\n\tPCyl, Sph.";
- #define FXC 1.12837916709551257390
- #define FYC 1.77245385090551602729
- #define ONEEPS 1.0000001
- FORWARD(s_forward); /* spheroid */
- if ((xy.y = 1. - sin(lp.phi)) <= 0.)
- xy.y = 0.;
- else
- xy.y = sqrt(xy.y);
- xy.x = FXC * lp.lam * xy.y;
- xy.y = FYC * (1. - xy.y);
- return (xy);
- }
- INVERSE(s_inverse); /* spheroid */
- lp.phi = xy.y / FYC - 1.;
- if (fabs(lp.phi = 1. - lp.phi * lp.phi) < 1.)
- lp.phi = asin(lp.phi);
- else if (fabs(lp.phi) > ONEEPS) I_ERROR
- else lp.phi = lp.phi < 0. ? -HALFPI : HALFPI;
- if ((lp.lam = 1. - sin(lp.phi)) <= 0.)
- lp.lam = 0.;
- else
- lp.lam = xy.x / (FXC * sqrt(lp.lam));
- return (lp);
- }
- FREEUP; if (P) pj_dalloc(P); }
- ENTRY0(collg) P->es = 0.; P->inv = s_inverse; P->fwd = s_forward; ENDENTRY(P)