How to bring map in rviz (indigo-gazebo)

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If I have understood well, you would like to load a map on Rviz. To load a map on Rviz you have two options:

1) via a launch file

2) do it manually. Open a terminal and go to the directory where you have put your map file and run:

rosrun map_server map_server sample.yaml

After you run rviz, (e.g., rosrun rviz rviz), add Map from the bottom left tab. Then, under the topic section choose /map.