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#include <u.h>
#include <libc.h>
#include "map.h"
static double scale;
static int
Xgall(struct place *place, double *x, double *y)
{
/* two ways to compute tan(place->nlat.l/2) */
if(fabs(place->nlat.s)<.1)
*y = sin(place->nlat.l/2)/cos(place->nlat.l/2);
else
*y = (1-place->nlat.c)/place->nlat.s;
*x = -scale*place->wlon.l;
return 1;
}
proj
gall(double par)
{
double coshalf;
if(fabs(par)>80)
return 0;
par *= RAD;
coshalf = cos(par/2);
scale = cos(par)/(2*coshalf*coshalf);
return Xgall;
}
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