Create the Python publisher/subscriber
--------------------------------------

- Create the catkin workspace directory and package:

   mkdir -p catkin_ws/src
   cd catkin_ws/src
   catkin_init_workspace
   catkin_create_pkg python_localiser rospy geometry_msgs

- Add a directory for the python scripts:

   mkdir -p python_localiser/scripts
   cd python_localiser/scripts

- Create publisher.py (don't forget to make it executable).

- Build and source it:

   cd catkin_ws/src
   catkin_make
   source devel/setup.bash

- Run it (in seperate terminals):

   roscore

   rosrun python_localiser publisher.py

   rostopic echo /robot_location

- Create subscriber.py.

- Run it:

   rosrun python_localiser subscriber

Create the C++ publisher/subscriber
-----------------------------------

   cd catkin_ws/src
   catkin_create_pkg cpp_localiser roscpp geometry_msgs

- Create publisher.cpp.

- Edit CMakeLists.txt

  add_executable(publisher src/publisher.cpp)
  target_link_libraries(publisher ${catkin_LIBRARIES})

- Create subscriber.cpp.

- Edit CMakeLists.txt

  add_executable(subscriber src/subscriber.cpp)
  target_link_libraries(subscriber ${catkin_LIBRARIES})




