1 files changed, 73 insertions, 0 deletions
diff --git a/navit/tools/gpx2navit_txt/src/geod_inv.c b/navit/tools/gpx2navit_txt/src/geod_inv.c
new file mode 100644
index 000000000..d938da8a3
--- /dev/null
+++ b/navit/tools/gpx2navit_txt/src/geod_inv.c
@@ -0,0 +1,73 @@
+#ifndef lint
+static const char SCCSID[] =
+    "@(#)geod_inv.c	4.5	95/09/23	GIE	REL";
+#endif
+# include "projects.h"
+# include "geodesic.h"
+# define DTOL	1e-12
+void geod_inv(void)
+{
+    double th1,
+	th2,
+	thm,
+	dthm,
+	dlamm,
+	dlam,
+	sindlamm,
+	costhm,
+	sinthm,
+	cosdthm,
+	sindthm, L, E, cosd, d, X, Y, T, sind, tandlammp, u, v, D, A, B;
+
+    if (ellipse) {
+	th1 = atan(onef * tan(phi1));
+	th2 = atan(onef * tan(phi2));
+    } else {
+	th1 = phi1;
+	th2 = phi2;
+    }
+    thm = .5 * (th1 + th2);
+    dthm = .5 * (th2 - th1);
+    dlamm = .5 * (dlam = adjlon(lam2 - lam1));
+    if (fabs(dlam) < DTOL && fabs(dthm) < DTOL) {
+	al12 = al21 = geod_S = 0.;
+	return;
+    }
+    sindlamm = sin(dlamm);
+    costhm = cos(thm);
+    sinthm = sin(thm);
+    cosdthm = cos(dthm);
+    sindthm = sin(dthm);
+    L = sindthm * sindthm + (cosdthm * cosdthm - sinthm * sinthm)
+	* sindlamm * sindlamm;
+    d = acos(cosd = 1 - L - L);
+    if (ellipse) {
+	E = cosd + cosd;
+	sind = sin(d);
+	Y = sinthm * cosdthm;
+	Y *= (Y + Y) / (1. - L);
+	T = sindthm * costhm;
+	T *= (T + T) / L;
+	X = Y + T;
+	Y -= T;
+	T = d / sind;
+	D = 4. * T * T;
+	A = D * E;
+	B = D + D;
+	geod_S = geod_a * sind * (T - f4 * (T * X - Y) +
+				  f64 * (X * (A + (T - .5 * (A - E)) * X) -
+					 Y * (B + E * Y) + D * X * Y));
+	tandlammp = tan(.5 * (dlam - .25 * (Y + Y - E * (4. - X)) *
+			      (f2 * T + f64 * (32. * T - (20. * T - A)
+					       * X - (B +
+						      4.) * Y)) *
+			      tan(dlam)));
+    } else {
+	geod_S = geod_a * d;
+	tandlammp = tan(dlamm);
+    }
+    u = atan2(sindthm, (tandlammp * costhm));
+    v = atan2(cosdthm, (tandlammp * sinthm));
+    al12 = adjlon(TWOPI + v - u);
+    al21 = adjlon(TWOPI - v - u);
+}