Robot Operating System Cookbook

Getting ready

A bag file is a container of messages on ROS topics published during the execution of the system, and this allows us to play them back virtually as a real system, even with time delays, since all messages are recorded with a timestamp and a header.

The ROS bag file stores data in a particular binary format for extremely fast recording throughput. Additionally, the size of the bag file is very important. Nonetheless, there is an option to compress the file on the fly with the bz2 algorithm using the -j parameter. Since each and every message is recorded along with the topic and publisher, this enables us to selectively specify which topics to record or record them all using the -a parameter. Similarly, we can also select a particular ...