EVOLUTION-MANAGER

Edit File: PJ_gall.c

#define PJ_LIB__ #include <math.h> #include "projects.h" PROJ_HEAD(gall, "Gall (Gall Stereographic)") "\n\tCyl, Sph"; #define YF 1.70710678118654752440 #define XF 0.70710678118654752440 #define RYF 0.58578643762690495119 #define RXF 1.41421356237309504880 static XY s_forward (LP lp, PJ *P) { /* Spheroidal, forward */ XY xy = {0.0,0.0}; (void) P; xy.x = XF * lp.lam; xy.y = YF * tan(.5 * lp.phi); return xy; } static LP s_inverse (XY xy, PJ *P) { /* Spheroidal, inverse */ LP lp = {0.0,0.0}; (void) P; lp.lam = RXF * xy.x; lp.phi = 2. * atan(xy.y * RYF); return lp; } PJ *PROJECTION(gall) { P->es = 0.0; P->inv = s_inverse; P->fwd = s_forward; return P; }