ref: 94916808dd9a53ac297ab537851791894b919828
dir: /sys/src/cmd/map/libmap/bonne.c/
#include <u.h> #include <libc.h> #include "map.h" static struct coord stdpar; static double r0; static Xbonne(struct place *place, double *x, double *y) { double r, alpha; r = r0 - place->nlat.l; if(r<.001) if(fabs(stdpar.c)<1e-10) alpha = place->wlon.l; else if(fabs(place->nlat.c)==0) alpha = 0; else alpha = place->wlon.l/(1+ stdpar.c*stdpar.c*stdpar.c/place->nlat.c/3); else alpha = place->wlon.l * place->nlat.c / r; *x = - r*sin(alpha); *y = - r*cos(alpha); return(1); } proj bonne(double par) { if(fabs(par*RAD) < .01) return(Xsinusoidal); deg2rad(par, &stdpar); r0 = stdpar.c/stdpar.s + stdpar.l; return(Xbonne); }