1 #include <u.h>
2 #include <libc.h>
3 #include "map.h"
4 
5 static int
6 Xmollweide(struct place *place, double *x, double *y)
7 {
8 	double z;
9 	double w;
10 	z = place->nlat.l;
11 	if(fabs(z)<89.9*RAD)
12 		do {	/*newton for 2z+sin2z=pi*sin(lat)*/
13 			w = (2*z+sin(2*z)-PI*place->nlat.s)/(2+2*cos(2*z));
14 			z -= w;
15 		} while(fabs(w)>=.00001);
16 	*y = sin(z);
17 	*x = - (2/PI)*cos(z)*place->wlon.l;
18 	return(1);
19 }
20 
21 proj
22 mollweide(void)
23 {
24 	return(Xmollweide);
25 }