The main task while creating a launch file for the gmapping process is to set the parameters for the slam_gmapping node and the move_base node. The slam_gmapping node is the core node inside the ROS Gmapping package. The slam_gmapping node subscribes the laser data (sensor_msgs/LaserScan) and the TF data, and publishes the occupancy grid map data as output (nav_msgs/OccupancyGrid). This node is highly configurable and we can fine tune the parameters to improve the mapping accuracy. The parameters are mentioned at http://wiki.ros.org/gmapping.
The next node we have to configure is the move_base node. The main parameters we need to configure are the global and local costmap parameters, the local planner, ...
