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Scan message must contain angles from -x to x

asked 2015-06-08 21:30:06 -0500

Leejamin gravatar image

updated 2015-07-16 08:50:33 -0500

mgruhler gravatar image

I follow the tutorial turtlebot_simulator to make a map in a simulated world.But when I run

roslaunch turtlebot_gazebo gmapping_demo.launch

a error that scan message must contain angles from -x to x occurs, as show below. How to deal with it.

[ERROR] [1433813576.466253926, 24.270000000]: Scan message must contain angles from -x to x, i.e. angle_min = -angle_max

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I am facing the same issue, any possible solution?

tosandip gravatar image tosandip  ( 2015-07-10 14:59:51 -0500 )edit

me too , do you have any possible solution

forinkzan gravatar image forinkzan  ( 2015-07-14 22:12:06 -0500 )edit

No i have not found any.. starting looking at jackal robot.

tosandip gravatar image tosandip  ( 2015-07-15 08:30:58 -0500 )edit

I have the same problem. This is the new behaviour in the latest ros-indigo-gmapping-1.3.7 package. CHANGELOG.rst says: .... * Added cfloat include * Change arbitrary constant to FLT_EPSILON * Added check that scan goes from -x to x .......

chuong gravatar image chuong  ( 2015-07-15 19:40:34 -0500 )edit

6 Answers

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answered 2015-07-31 02:11:57 -0500

Vincent Rabaud gravatar image

Hi all, thank you for sharing the data. A fix was merged upstream in 1.3.8: it just reached shadow fixed so please test. The fix centers the scan before sending them to gmapping, whether they're slightly / completely off-centered or even upside-down.

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answered 2015-07-15 22:32:04 -0500

chuong gravatar image

updated 2015-07-15 22:43:44 -0500

This error is due to recent change in gmapping package. This can be fixed by modifying and recompiling the gmapping package as follows:

$ wget
$ mkdir -p ~/catkin_ws/src
$ cd ~/catkin_ws/src
$ catkin_init_workspace
$ tar xvf ../../ros-indigo-gmapping_1.3.7.orig.tar.gz
$ mv ros-indigo-gmapping-1.3.7/ gmapping
$ gedit gmapping/src/slam_gmapping.cpp
Change line 409 from:
  if (fabs(fabs(scan.angle_min) - fabs(scan.angle_max)) > FLT_EPSILON)
  if (fabs(fabs(scan.angle_min) - fabs(scan.angle_max)) > 0.003) // this is the value for Kinect
Save and close the file. Go back to commandline:

$ cd ..
$ catkin_make
$ sudo cp devel/lib/gmapping/slam_gmapping* /opt/ros/indigo/lib/gmapping/
This works for me.

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+1 only as a temporary workaround for the particular usecase (turtlebot_gazebo in this case). Since gmapping is a package that's fundamental enough, we need a permanent solution. I've opened a related PR.

130s gravatar image 130s  ( 2015-07-16 00:03:22 -0500 )edit

why is this only working for turtlebot_gazebo?

Salocin808 gravatar image Salocin808  ( 2015-07-16 09:16:23 -0500 )edit

This is not working for me. Followed the instructions but still getting same error. Any ideas? (I'm using Ubuntu 14.04.2 LTS and Turtlebot 2)

Salocin808 gravatar image Salocin808  ( 2015-07-16 09:50:56 -0500 )edit

@Salocin808 Instant workaround (not a "solution") can be to play with FLT_EPSILON value that works for you. Once you find the smallest working value sharing it with us would be beneficial.

130s gravatar image 130s  ( 2015-07-16 09:56:51 -0500 )edit

@130s Ok thanks for your help! I am already at home but will try it tomorrow morning.

Salocin808 gravatar image Salocin808  ( 2015-07-16 10:23:31 -0500 )edit

@130s I changed the error message so that it prints out the difference between the angles:

[ERROR] [1437121911.683298899]: Edited: Scan message must contain angles from -x to x, i.e. angle_min (0.513185) = -angle_max (0.499907). min-max = 0.013278

Maybe EPSILON should be 0.03?

Salocin808 gravatar image Salocin808  ( 2015-07-17 03:40:01 -0500 )edit

please guys, don't try to find workarounds: report the bug at least; better, help fixing it :)

Vincent Rabaud gravatar image Vincent Rabaud  ( 2015-07-18 05:07:42 -0500 )edit

well, after changing the value to 0.03 I never had problems.. where should I report the bug?

Salocin808 gravatar image Salocin808  ( 2015-07-21 02:48:10 -0500 )edit

answered 2015-08-13 13:00:39 -0500

stevenwaslander gravatar image

updated 2015-08-13 13:01:21 -0500

Combining two answers, this now works, assuming you have a catkin workspace set up already:

cd ~/catkin_ws/src
tar xvf ../../ros-indigo-gmapping_1.3.8.orig.tar.gz   
mv ros-indigo-gmapping-1.3.8/ gmapping
sudo cp devel/lib/gmapping/slam_gmapping* /opt/ros/indigo/lib/gmapping/
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but I could not find gmapping directory after I run 'catkin_make' command. my machine environment is raspberry Pi 3

Oakafka gravatar image Oakafka  ( 2016-05-27 10:02:23 -0500 )edit

answered 2016-05-27 09:59:09 -0500

Oakafka gravatar image

but I can not find gmapping/ in devel/lib after I run 'catkin_make'

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answered 2015-07-16 10:05:01 -0500

130s gravatar image

updated 2015-07-17 12:55:28 -0500

While @chuong's answer can be referenced as a temporary workaround, I filed a discussion ticket in gmapping community for the permanent solution.

UPDATE @Vincent Rabaud opened a pull request that can be the permanent solution for this issue. Try it out, and give feedback in the ticket.

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can anybody please send me a failing rosbag ? My personal email is

Vincent Rabaud gravatar image Vincent Rabaud  ( 2015-07-16 11:55:06 -0500 )edit
130s gravatar image 130s  ( 2015-07-16 12:42:02 -0500 )edit

@Salocin808 Permanent, general solution is discussed in this ticket. And I've already did debug print hack haha

130s gravatar image 130s  ( 2015-07-17 08:44:33 -0500 )edit

I tested @Vincent Rabaud's patch and found gmapping didn't run as expected. It printed "Registering First Scan" then stopped updating. There was no other output until being killed.

chuong gravatar image chuong  ( 2015-07-19 19:51:25 -0500 )edit

For a pull request, let's keep discussing in the pull request page instead of distributing info at multiple places.

130s gravatar image 130s  ( 2015-07-23 21:55:54 -0500 )edit

answered 2016-03-05 01:45:45 -0500

updated 2016-03-05 01:49:34 -0500

Now you just need to download the latest version of gmapping(1.3.8), extract it into your catkin_ws/src.


$ catkin_make


$ sudo cp devel/lib/gmapping/slam_gmapping* /opt/ros/indigo/lib/gmapping/

Hope this works for you :)

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Asked: 2015-06-08 21:30:06 -0500

Seen: 1,653 times

Last updated: Mar 05 '16