1 files changed, 50 insertions, 0 deletions
diff --git a/src/projections/wag3.cpp b/src/projections/wag3.cpp
new file mode 100644
index 00000000..bb1b4d49
--- /dev/null
+++ b/src/projections/wag3.cpp
@@ -0,0 +1,50 @@
+#define PJ_LIB__
+
+#include <errno.h>
+#include <math.h>
+
+#include "projects.h"
+
+PROJ_HEAD(wag3, "Wagner III") "\n\tPCyl, Sph\n\tlat_ts=";
+
+#define TWOTHIRD 0.6666666666666666666667
+
+namespace { // anonymous namespace
+struct pj_opaque {
+	double	C_x;
+};
+} // anonymous namespace
+
+
+static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
+    XY xy = {0.0,0.0};
+	xy.x = static_cast<struct pj_opaque*>(P->opaque)->C_x * lp.lam * cos(TWOTHIRD * lp.phi);
+	xy.y = lp.phi;
+	return xy;
+}
+
+
+static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
+    LP lp = {0.0,0.0};
+	lp.phi = xy.y;
+	lp.lam = xy.x / (static_cast<struct pj_opaque*>(P->opaque)->C_x * cos(TWOTHIRD * lp.phi));
+	return lp;
+}
+
+
+PJ *PROJECTION(wag3) {
+	double ts;
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque)));
+    if (nullptr==Q)
+        return pj_default_destructor(P, ENOMEM);
+
+    P->opaque = Q;
+
+	ts = pj_param (P->ctx, P->params, "rlat_ts").f;
+	static_cast<struct pj_opaque*>(P->opaque)->C_x = cos (ts) / cos (2.*ts/3.);
+	P->es = 0.;
+    P->inv = s_inverse;
+    P->fwd = s_forward;
+
+    return P;
+}