+#ifndef COMPASS_H
+#define COMPASS_H
+
+#define PI 3.14159265358979323846
+
+INLINE float deg2rad(float deg)
+{
+ return deg * PI / 180;
+}
+
+INLINE float rad2deg(float rad)
+{
+ return rad * 180 / PI;
+}
+
+float distance(float lat1, float lon1, float lat2, float lon2);
+int bearing(float lat1, float lon1, float lat2, float lon2);
+const char *compass_heading(int bearing);
+
+#endif /* COMPASS_H */