# Covariance matrix for the PoseWithCovariance in Odometry.msg

To disclaim, I do not have a solid understanding of covariance matrices. I'm also still using electric.

The Odometry.msg includes a geometry_msgs/PoseWithCovariance, which itself includes a geometry_msgs/Pose and a 6x6 covariance matrix. If the Point has three variables and the Quaternion has four variables, why isn't the covariance matrix 7x7?

Also, are the comments in the PoseWithCovariance.msg file inaccurate when they refer to the roll, pitch and yaw instead of to a quaternion?