/Proj4/PJ_gall.c

 1#ifndef lint
 2static const char SCCSID[]="@(#)PJ_gall.c	4.1	94/02/15	GIE	REL";
 3#endif
 4#define PJ_LIB__
 5#include	"projects.h"
 6PROJ_HEAD(gall, "Gall (Gall Stereographic)") "\n\tCyl, Sph";
 7#define YF	1.70710678118654752440
 8#define XF	0.70710678118654752440
 9#define RYF	0.58578643762690495119
10#define RXF	1.41421356237309504880
11FORWARD(s_forward); /* spheroid */
12	xy.x = XF * lp.lam;
13	xy.y = YF * tan(.5 * lp.phi);
14	return (xy);
15}
16INVERSE(s_inverse); /* spheroid */
17	lp.lam = RXF * xy.x;
18	lp.phi = 2. * atan(xy.y * RYF);
19	return (lp);
20}
21FREEUP; if (P) pj_dalloc(P); }
22ENTRY0(gall) P->es = 0.; P->inv = s_inverse; P->fwd = s_forward; ENDENTRY(P)