Attention: Answers.ros.org is deprecated as of August the 11th, 2023. Please visit robotics.stackexchange.com to ask a new question. This site will remain online in read-only mode during the transition and into the foreseeable future. Selected questions and answers have been migrated, and redirects have been put in place to direct users to the corresponding questions on Robotics Stack Exchange. Additional details are available here.

rostopic echo doesn't return any data

asked 2022-01-09 13:43:06 -0600

jgauthier
21 ●6 ●12 ●15

So, kind of a weird problem.

I set up ROS on an RPi with a kinect. I am generating a map with slam_gmapping. It works - but it's terribly slow. So, I decided to off load the SLAM process to an actual PC that is much faster.

I did - and it seems to be working fine. However, on the raspberry pi I can no longer see the map. for instance rostopic echo /map never returns, which tells me nothing is being published.

However, on the PC I can echo the map just fine.

Likewise, I have depthimage_to_laserscan running on the Rpi. On both the pi and the PC I can easily echo /scan.

It seems to be specific to running slam_gmapping on the PC that I can't echo the map on the Rpi.

What could cause that?

edit retag flag offensive close merge delete

add a comment

1 Answer

Sort by » oldest newest most voted

answered 2022-01-10 05:39:04 -0600

osilva

1650 ●3 ●172 ●19 https://github.com/rob...

Please take a look at previous question:#q322394

The most common issue is: setting ROS_HOSTNAME or ROS_MASTER_URI to a hostname without a way for the machines to resolve the hostnames into IPs (or setting ROS_IP to a hostname, instead of an IP).

edit flag offensive delete link

Comments

I'm using all IPs. But this doesn't make sense to me. On machine A (which is running roscore) I can echo all the topics except for the one published by machine B. On machine B, I can echo all topics.

jgauthier ( 2022-01-10 10:31:04 -0600 )edit

do you use different namespaces? if so you have to add that namespace in front of the topic. If not I agree that the problem is mist likely with your ROS_HOSTNAME ROS_MASTER_URI ROS_IP setup.

crnewton ( 2022-01-15 05:43:32 -0600 )edit

add a comment

Question Tools

2 followers

Stats

Asked: 2022-01-09 13:43:06 -0600

Seen: 630 times

Last updated: Jan 10 '22

rostopic echo doesn't return any data edit

1 Answer

Comments

Question Tools

Stats

Related questions

rostopic echo doesn't return any data