xref: /plan9/sys/src/cmd/map/libmap/cylequalarea.c (revision 59cc4ca53493a3c6d2349fe2b7f7c40f7dce7294)
1 #include <u.h>
2 #include <libc.h>
3 #include "map.h"
4 
5 static double a;
6 
7 static int
Xcylequalarea(struct place * place,double * x,double * y)8 Xcylequalarea(struct place *place, double *x, double *y)
9 {
10 	*x = - place->wlon.l * a;
11 	*y = place->nlat.s;
12 	return(1);
13 }
14 
15 proj
cylequalarea(double par)16 cylequalarea(double par)
17 {
18 	struct coord stdp0;
19 	if(par > 89.0)
20 		return(0);
21 	deg2rad(par, &stdp0);
22 	a = stdp0.c*stdp0.c;
23 	return(Xcylequalarea);
24 }
25