1 files changed, 13 insertions, 0 deletions
diff --git a/libtellurian_coarse_distance_radians.c b/libtellurian_coarse_distance_radians.c
new file mode 100644
index 0000000..eb9cac0
--- /dev/null
+++ b/libtellurian_coarse_distance_radians.c
@@ -0,0 +1,13 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+double
+libtellurian_coarse_distance_radians(double latitude1, double longitude1,
+                                     double latitude2, double longitude2)
+{
+	double h = fma(haversin(longitude2 - longitude1),
+	               cos(latitude1) * cos(latitude2),
+	               haversin(latitude2 - latitude1));
+	return 2.0 * LIBTELLURIAN_AUTHALIC_RADIUS * asin(sqrt(h));
+}