New

git-svn-id: http://svn.osgeo.org/metacrs/proj/trunk@776 4e78687f-474d-0410-85f9-8d5e500ac6b2

1 files changed, 59 insertions, 0 deletions

diff --git a/src/geod_inv.c b/src/geod_inv.c
new file mode 100644
index 00000000..f41d58af
--- /dev/null
+++ b/src/geod_inv.c
@@ -0,0 +1,59 @@
+#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 = 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;
+		S = 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 {
+		S = 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);
+}