# How do you convert a quaternion into an axis-angle representation?

Hello,

I'd like to convert an orientation from geometry_msgs::Quaternion to an axis-angle representation (http://en.wikipedia.org/wiki/Axis-angle_representation). Similarly, I'd like to convert back to a quaternion from an axis-angle value. What ROS libraries are available to preform these conversions?

Thanks

I answered this question, then edited that and it disappeared. It does not allow me to answer again! The best I could do: https://gist.github.com/e5170cf046b8001f4e65