Hi,
For /zed/odom, you may ask on
https://github.com/stereolabs/zed-ros-wrapper/issuesTo evaluate it, you may need a GPS RTK if you are outdoor, or tracking system (e.g., VICON, OptiTrack...) indoor. Then having ground truth poses along odometry poses, you could evaluate its accuracy with TUM's
evaluation tools.
cheers,
Mathieu