Migrate to radians instead of degrees to lessen conversion errors

utilities/include/geodata.hpp

@@ -41,11 +41,16 @@ namespace geodata
 
   static inline double toRadians(double value) { return value * M_PI / 180; }
 
-  static inline double normalize(double value)
+  static inline double normalizeD(double value)
   {
     return fmod(value + 360, 360);
   }
 
+  static inline double normalizeR(double value)
+  {
+    return value < 0 ? 2 * M_PI + value : value;
+  }
+
   // Input and Output in degrees
   static inline double bearingDD(double fromLatitude,
                                  double fromLongitude,
@@ -58,7 +63,22 @@ namespace geodata
                sin(toRadians(fromLatitude)) * cos(toRadians(toLatitude)) *
                    cos(toRadians(toLongitude) - toRadians(fromLongitude));
 
-    return normalize(toDegrees(atan2(y, x)));
+    return normalizeD(toDegrees(atan2(y, x)));
+  }
+
+  // Input in degrees, Output in radians
+  static inline double bearingDR(double fromLatitude,
+                                 double fromLongitude,
+                                 double toLatitude,
+                                 double toLongitude)
+  {
+    double y = sin(toRadians(toLongitude) - toRadians(fromLongitude)) *
+               cos(toRadians(toLatitude));
+    double x = cos(toRadians(fromLatitude)) * sin(toRadians(toLatitude)) -
+               sin(toRadians(fromLatitude)) * cos(toRadians(toLatitude)) *
+                   cos(toRadians(toLongitude) - toRadians(fromLongitude));
+
+    return normalizeR(atan2(y, x));
   }
 
   // Input in degrees, Output in metres