diff options
Diffstat (limited to 'src/PJ_collg.c')
| -rw-r--r-- | src/PJ_collg.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/src/PJ_collg.c b/src/PJ_collg.c new file mode 100644 index 00000000..9bcc24fa --- /dev/null +++ b/src/PJ_collg.c @@ -0,0 +1,32 @@ +#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) |