diff --git a/external/L.Geodesic.js b/external/L.Geodesic.js
index 09d58791..b2bf8339 100644
--- a/external/L.Geodesic.js
+++ b/external/L.Geodesic.js
@@ -174,10 +174,9 @@ Modified by qnstie 2013-07-17 to maintain compatibility with Leaflet.draw
 
       var calcLatLngAtAngle = function(angle) {
         var lat = Math.asin(sinCentreLat*cosRadRadius + cosCentreLat*sinRadRadius*Math.cos(angle));
+        var lng = centreLng + Math.atan2(Math.sin(angle)*sinRadRadius*cosCentreLat, cosRadRadius-sinCentreLat*Math.sin(lat));
 
-        var lon = centreLng + Math.asin( Math.sin(angle) * sinRadRadius / cosCentreLat )
-
-        return L.latLng(lat * r2d,lon * r2d);
+        return L.latLng(lat * r2d,lng * r2d);
       }