how to convert pointcloud to laser scan in ros indigo

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Hi all, I am using ros indigo.I want to convert point cloud to laser scan data.I used freenect to collect kinect data( using kinect Xbox 360).Now I want to convert this data to lasercan data to construct 2D map.I read that we can use depthimage_to_laserscan package.I used the command rosrun depthimage_to_laserscan depthimage_to_laserscan image:=/camera/depth/image_raw,but it is not showing anything.I am new to ROS and someone please help.