Comment by gautam2410 for Do you have a map already or do you want to build a complete map of your environment? In the latter case, you could try the exploration module from: http://wiki.ros.org/nav2dIt completely explores an unknown environment and builds a map using 2D Laser-Scanner.

The same question has been asked [here](http://answers.ros.org/question/203867/how-to-instruct-a-robot-to-cover-the-whole-mapped-2d-area/) so I am not posting a new question. Can you please explain how to give the goal with an empty polygon? By unbounded search do you mean the total map coverage?