1 files changed, 43 insertions, 0 deletions
diff --git a/src/projections/boggs.cpp b/src/projections/boggs.cpp
new file mode 100644
index 00000000..119357c0
--- /dev/null
+++ b/src/projections/boggs.cpp
@@ -0,0 +1,43 @@
+#define PJ_LIB__
+#include <math.h>
+
+#include "projects.h"
+
+PROJ_HEAD(boggs, "Boggs Eumorphic") "\n\tPCyl, no inv, Sph";
+# define NITER	20
+# define EPS	1e-7
+# define FXC	2.00276
+# define FXC2	1.11072
+# define FYC	0.49931
+
+
+static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
+    XY xy = {0.0,0.0};
+	double theta, th1, c;
+	int i;
+	(void) P;
+
+	theta = lp.phi;
+	if (fabs(fabs(lp.phi) - M_HALFPI) < EPS)
+		xy.x = 0.;
+	else {
+		c = sin(theta) * M_PI;
+		for (i = NITER; i; --i) {
+			theta -= th1 = (theta + sin(theta) - c) /
+				(1. + cos(theta));
+			if (fabs(th1) < EPS) break;
+		}
+		theta *= 0.5;
+		xy.x = FXC * lp.lam / (1. / cos(lp.phi) + FXC2 / cos(theta));
+	}
+	xy.y = FYC * (lp.phi + M_SQRT2 * sin(theta));
+	return (xy);
+}
+
+
+
+PJ *PROJECTION(boggs) {
+    P->es = 0.;
+    P->fwd = s_forward;
+    return P;
+}