1 files changed, 40 insertions, 0 deletions
diff --git a/src/projections/eck5.cpp b/src/projections/eck5.cpp
new file mode 100644
index 00000000..f9f28460
--- /dev/null
+++ b/src/projections/eck5.cpp
@@ -0,0 +1,40 @@
+#define PJ_LIB__
+
+#include <math.h>
+
+#include "projects.h"
+
+PROJ_HEAD(eck5, "Eckert V") "\n\tPCyl, Sph";
+
+#define XF  0.44101277172455148219
+#define RXF 2.26750802723822639137
+#define YF  0.88202554344910296438
+#define RYF 1.13375401361911319568
+
+
+static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
+    XY xy = {0.0,0.0};
+    (void) P;
+    xy.x = XF * (1. + cos(lp.phi)) * lp.lam;
+    xy.y = YF * lp.phi;
+
+    return xy;
+}
+
+
+static LP s_inverse (XY xy, PJ *P) {           /* Spheroidal, inverse */
+    LP lp = {0.0,0.0};
+    (void) P;
+    lp.lam = RXF * xy.x / (1. + cos( lp.phi = RYF * xy.y));
+
+    return lp;
+}
+
+
+PJ *PROJECTION(eck5) {
+    P->es = 0.0;
+    P->inv = s_inverse;
+    P->fwd = s_forward;
+
+    return P;
+}