ROS Resources: Documentation | Support | Discussion Forum | Index | Service Status | ros @ Robotics Stack Exchange
Ask Your Question

Feeding different SLAM algorithm with the same bag file

asked 2020-02-20 10:54:28 -0500

sinsinsinsin gravatar image

updated 2020-02-26 14:06:42 -0500

Hi I am trying to feed gmapping with bag dataset from cartographer. But terminal shows the gmapping is hoping the data type of "sensor_msgs/LaserScan" while the cartographer dataset bag provides the topics of "horizontal_laser_2d","vertical_laser_2d" with data type "sensor_msgs/Multiecholaserscan".

So, generally, how do people do to fit the dataset type issue If they want to run different SLAM algorithm with the same bag dataset.

Thank you.


The correct way should be modify the cartographer launch file and lua file to "tell" the cartographer what's kind of sensor and topic we will use. But I managed found out the cartographer_turtlebot we have the related launch file and lua file in which the scan topic is "/scan" rather than "horziontal_laser_2d".

edit retag flag offensive close merge delete


The difference between an ordinary laser scan and a multi echo laser scan is explained in REP 138. It looks like the laser_proc package has a nodelet that can listen to Multiecholaserscan and can publish LaserScans. Do you know how to run / test that?

Wilco Bonestroo gravatar image Wilco Bonestroo  ( 2020-02-21 14:48:08 -0500 )edit

@xinxinxin: please mark the question as answered by clicking the checkmark to the left of the answer you feel is the answer.

We don't close questions here on ROS Answers when they are answered.

gvdhoorn gravatar image gvdhoorn  ( 2020-02-26 14:20:10 -0500 )edit

Hello, @sinsinsinsin can you elaborate further? I have this exact same issue but I have not been able to solve it.

I have my launch file which I use to run gmapping on other bag-files, but it doesn't work for cartographer bags because of this LaserScan VS MultiEchoLaserScan issue. Your solution says that the cartographer launch file and lua file need to be edited. But I need to run gmapping not cartographer and I already have my custom_gmapping.launch file and my custom.lua file.

How do I make it possible to run gmapping on the cartographer bag-file with my launch file?

TheLastMiniatureTitan gravatar image TheLastMiniatureTitan  ( 2023-03-20 07:21:25 -0500 )edit

1 Answer

Sort by ยป oldest newest most voted

answered 2020-02-21 09:22:40 -0500

Benji gravatar image

If I understood your question correctly, you could use rosbag API to get access to the bag data and modify it. (

Hope that helps :)

edit flag offensive delete link more

Question Tools

1 follower


Asked: 2020-02-20 10:54:28 -0500

Seen: 315 times

Last updated: Feb 26 '20