1 files changed, 54 insertions, 0 deletions
diff --git a/src/projections/nocol.cpp b/src/projections/nocol.cpp
new file mode 100644
index 00000000..541d08b2
--- /dev/null
+++ b/src/projections/nocol.cpp
@@ -0,0 +1,54 @@
+#define PJ_LIB__
+
+#include <math.h>
+
+#include "projects.h"
+
+PROJ_HEAD(nicol, "Nicolosi Globular") "\n\tMisc Sph, no inv";
+
+#define EPS 1e-10
+
+
+static XY s_forward (LP lp, PJ *P) {           /* Spheroidal, forward */
+    XY xy = {0.0,0.0};
+    (void) P;
+
+    if (fabs(lp.lam) < EPS) {
+        xy.x = 0;
+        xy.y = lp.phi;
+    } else if (fabs(lp.phi) < EPS) {
+        xy.x = lp.lam;
+        xy.y = 0.;
+    } else if (fabs(fabs(lp.lam) - M_HALFPI) < EPS) {
+        xy.x = lp.lam * cos(lp.phi);
+        xy.y = M_HALFPI * sin(lp.phi);
+    } else if (fabs(fabs(lp.phi) - M_HALFPI) < EPS) {
+        xy.x = 0;
+        xy.y = lp.phi;
+    } else {
+        double tb, c, d, m, n, r2, sp;
+
+        tb = M_HALFPI / lp.lam - lp.lam / M_HALFPI;
+        c = lp.phi / M_HALFPI;
+        d = (1 - c * c)/((sp = sin(lp.phi)) - c);
+        r2 = tb / d;
+        r2 *= r2;
+        m = (tb * sp / d - 0.5 * tb)/(1. + r2);
+        n = (sp / r2 + 0.5 * d)/(1. + 1./r2);
+        xy.x = cos(lp.phi);
+        xy.x = sqrt(m * m + xy.x * xy.x / (1. + r2));
+        xy.x = M_HALFPI * ( m + (lp.lam < 0. ? -xy.x : xy.x));
+        xy.y = sqrt(n * n - (sp * sp / r2 + d * sp - 1.) /
+            (1. + 1./r2));
+        xy.y = M_HALFPI * ( n + (lp.phi < 0. ? xy.y : -xy.y ));
+    }
+    return (xy);
+}
+
+
+PJ *PROJECTION(nicol) {
+    P->es = 0.;
+    P->fwd = s_forward;
+
+    return P;
+}