In this section, we explore the TurtleBot's odometry. The general definition of odometry is the use of data from motion sensors to estimate change in position over time. Odometry is used by the TurtleBot to estimate its position and orientation relative to a starting location given in terms of an x and y position and an orientation around the z (upward) axis. The topic is /odom and the command to view the form of the /odom message is as follows:
$ rostopic echo /odom
When you execute this echo command, the output will be updated continuously on the screen. However, we wish to display TurtleBot's motion using rviz. When the odometry option is chosen in rviz, the TurtleBot's position and orientation will be displayed with arrows that are generated as TurtleBot moves.
