Follow the steps to recreate the project as shown in the video

• Go to Robot Ignite Academy. You will need to signup if you have not registered already.
• In the home page, choose the course ROS Navigation in 5 Days

Once the course page opens select start course option

You should be greeted with the workspace like following (it will take a while to load the full page)

• Open the Units menu from bottom left of the screen and select the Unit 2: Mapping

• Start the gmapping package by executing the following command in a SHELL (there are four SHELL in the bottom of the screen)
  

  $ roslaunch turtlebot_navigation_gazebo gmapping_demo.launch

• We will need a RVIZ windown to see the map visualization. Open a graphical interface window (see image)

• Enter the following command in another SHELL to start the RVIZ visualization
  

  $ rosrun rviz rviz

The above command will load the RVIZ in the graphical interface window as shown. We will add displays to the RVIZ window (as shown in image)

• RobotModel
• LaserScan
• Map

• Make the following settings
  • Map : set Topic to /map
  • Laser : set Topic to /kobuki/laser/scan

Once the above settings are made, you should start to see the visualization in the RVIZ window

• Now that mapping package is working, we will move the robot around to capture more data. To do so we will use the keyboard teleoperation, execute the following commands in a SHELL

$ roslaunch turtlebot_teleop keyboard_teleop.launch

Use the keys I(forward), J(left), L(right), M(backwards) to move the robot around. As you move the robot around the MAP in rviz should grow

• To save the current map, execute the following command in a new SHELL

$ cd ~catkin_ws/src $ mkdir maps $ cd maps $ rosrun map_server map_saver -f my_map $ ls

You should see two new files created inside the ~/catkin_ws/src/maps directory

• my_map.pgm
• my_map.yaml

Now we can load this map to the map_server with the following command

$ rosrun map_server map_server my_map.yaml

The above command will start a map node with the map data in it. There is an alternate way to provide this map with the launch file. To provide the map using a launch file lets create a new package called provide_map. Execute the following commands in a SHELL

$ cd ~catkin_ws/src

$ catkin_create_pkg provide_map

$ cd provide_map

$ mkdir launch

$ mv ../maps . cd launch

$ touch provide_map.launch

The above commands create a new package by name provide_map and create a directory named launch inside the new package, it copies the maps directory (where we saved the maps) to inside the package and lastly creates a launch file provide_map.launch. Put the following content inside the launch file

<launch> 
  <arg name="map_file" value="/home/user/catkin_ws/src/provide_map/maps/my_map.yaml">
  </arg> 
  <node pkg="map_server" type="map_server" name="map_server" args="$(arg map_file)"> 
  </node> 
</launch>

To test everythin works well we can run this launch file. Close the running instance of RVIZ and in the same SHELL use the following commands

$ roslaunch provide_map provide_map.launch

You should see the RVIZ window load with map. With this we finish this part.