+#define VIK_FEET_TO_METERS(X) (X/VIK_FEET_IN_METER)
+
+/* MPS - Metres Per Second */
+/* MPH - Metres Per Hour */
+#define VIK_MPH_IN_MPS 2.23693629
+#define VIK_MPS_TO_MPH(X) (X*VIK_MPH_IN_MPS)
+#define VIK_MPH_TO_MPS(X) (X/VIK_MPH_IN_MPS)
+
+/* KPH - Kilometres Per Hour */
+#define VIK_KPH_IN_MPS 3.6
+#define VIK_MPS_TO_KPH(X) (X*VIK_KPH_IN_MPS)
+#define VIK_KPH_TO_MPS(X) (X/VIK_KPH_IN_MPS)
+
+#define VIK_KNOTS_IN_MPS 1.94384449
+#define VIK_MPS_TO_KNOTS(X) (X*VIK_KNOTS_IN_MPS)
+#define VIK_KNOTS_TO_MPS(X) (X/VIK_KNOTS_IN_MPS)