[formulas] Fix calculation of t for finding the geodesic scale (M12)

BoostGSoC18 · Jun 13, 2018 · d11b716 · d11b716
1 parent 2cba2fa
commit d11b716
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/include/boost/geometry/formulas/karney_direct.hpp b/include/boost/geometry/formulas/karney_direct.hpp
@@ -250,7 +250,7 @@ class karney_direct
 
             // Find the geodesic scale.
             CT const t = k2 * (sin_sigma2 - sin_sigma1) *
-                              (sin_sigma2 * sin_sigma1) / (dn1 + dn2);
+                              (sin_sigma2 + sin_sigma1) / (dn1 + dn2);
 
             result.geodesic_scale = cos_sigma12 +
                                     (t * sin_sigma2 - cos_sigma2 * J12) *