// reposition the cloud layer at the specified origin and orientation
void reposition( sgVec3 p, sgVec3 up, double lon, double lat, double alt, double dt, float direction, float speed);
// reposition the cloud layer at the specified origin and orientation
void reposition( sgVec3 p, sgVec3 up, double lon, double lat, double alt, double dt, float direction, float speed);