How to use laser_assembler correctly

Question

Hello, I am trying to use the laser_assembler node but have had no luck getting it to work. I am using this tutorial on How to assemble laser scan lines into a composite point cloud. I'm reading in the laser scan data provided by ROS which can be found on the same page as the tutorial.

So far I have moved all of the laser_assembler files into there own folder in my ros_workspace. I have also copied the launch file (found on the tutorial page) and placed it within the "Example" folder within the laser_assembler node, making changes to the package name. I then launch the laser_scan_assembler.launch file along wit the periodic_snapshotter file. I then run rosbag play laser.bag and open up Rviz. I subscribe to the correct topic but nothing shows up in Rviz.

Can anyone help he clarify what I'm doing wrong and point me in the right direction?

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Originally posted by tyler258 on ROS Answers with karma: 93 on 2011-09-30

Post score: 0

Answer 1

The first thing that you should do would be to make sure that if you moved the laser_assembler files into your own folder you also changed the package names in the launch files. The next step would be to make sure that all nodes are running properly. For this, you can use:

rosnode list

Also, I noticed that you issued the command "rosbag play laser.bag", but you need to use the command "rosbag play --clock laser.bag" instead. This will replace the system time used by the laser assembler with the system time that was used during the recording of the rosbag. Otherwise, tf will be unable to re-create the correct transforms and no scans will be displayed.

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Originally posted by DimitriProsser with karma: 11163 on 2011-09-30

This answer was ACCEPTED on the original site

Post score: 1

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Original comments

Comment by tyler258 on 2011-10-03:
That fixed the problem. Thank you so much for helping me with all of my laser_pipeline node questions.