1 files changed, 58 insertions, 0 deletions
diff --git a/src/projections/rpoly.cpp b/src/projections/rpoly.cpp
new file mode 100644
index 00000000..a34f6171
--- /dev/null
+++ b/src/projections/rpoly.cpp
@@ -0,0 +1,58 @@
+#define PJ_LIB__
+
+#include <errno.h>
+#include <math.h>
+
+#include "projects.h"
+
+namespace { // anonymous namespace
+struct pj_opaque {
+    double  phi1;
+    double  fxa;
+    double  fxb;
+    int     mode;
+};
+} // anonymous namespace
+
+PROJ_HEAD(rpoly, "Rectangular Polyconic")
+    "\n\tConic, Sph, no inv\n\tlat_ts=";
+
+#define EPS 1e-9
+
+static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
+    XY xy = {0.0,0.0};
+    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
+    double fa;
+
+    if (Q->mode)
+        fa = tan(lp.lam * Q->fxb) * Q->fxa;
+    else
+        fa = 0.5 * lp.lam;
+    if (fabs(lp.phi) < EPS) {
+        xy.x = fa + fa;
+        xy.y = - P->phi0;
+    } else {
+        xy.y = 1. / tan(lp.phi);
+        xy.x = sin(fa = 2. * atan(fa * sin(lp.phi))) * xy.y;
+        xy.y = lp.phi - P->phi0 + (1. - cos(fa)) * xy.y;
+    }
+    return xy;
+}
+
+
+
+PJ *PROJECTION(rpoly) {
+    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;
+
+    if ((Q->mode = (Q->phi1 = fabs(pj_param(P->ctx, P->params, "rlat_ts").f)) > EPS)) {
+        Q->fxb = 0.5 * sin(Q->phi1);
+        Q->fxa = 0.5 / Q->fxb;
+    }
+    P->es = 0.;
+    P->fwd = s_forward;
+
+    return P;
+}