1 files changed, 36 insertions, 0 deletions
diff --git a/src/cmd/map/libmap/bonne.c b/src/cmd/map/libmap/bonne.c
new file mode 100644
index 00000000..858f0d69
--- /dev/null
+++ b/src/cmd/map/libmap/bonne.c
@@ -0,0 +1,36 @@
+#include <u.h>
+#include <libc.h>
+#include "map.h"
+
+static struct coord stdpar;
+static double r0;
+
+static int
+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);
+}