Rosject - (ROS Basics in 5 Days: Course Project) Laser scan, wall following behavior

Category:
Start Part I of rosject after “ROS Basics in 5 Days”
Goal:
Correctly interpret the laser scan data

What I did:
Output ranges from sensor_msgs::LaserScan message in terminal

Question:
From the Laser scan data, which one is front, left, right, back of the turtlebot?

Following the 2 pages Laser scan in myrosject, Incorrect Robot Scan values, they are interpreted as

ranges[0]: Back
ranges[180]: Right
ranges[360]: Front
ranges[540]: Left
ranges[719]: Back

For me, after several tests, I’m still not able to interpret them correctly.


(This picture includes the output of the laser scan data)

(Below is rostopic echo /scan)

It shows an inf value because the robot is too close to the wall. If you move it back, then you’ll see a reading that makes sense

Thanks for the help.