Exercise 5.1.....Path Planning part 2

Respected Professor, why is my map shown different and I can’t see anything on the map?
What I did was, I ran the command rosrun rviz rviz and added the map I had built previously for Path Planning part 1. But it shows something blank.


Remember that the navigation systems have to be launched first, otherwise RVIZ cant do anything. RVOZ just renders ros topic data, it doesn’t generate anything.