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nav_msgs/OccupancyGrid topic doesn't exist

asked 2018-04-18 15:11:46 -0500

FateInHaze gravatar image

Hi, I have set up a simple subsriber like the one in this tutorial and am trying to use it to get data from the nav_msgs/OccupancyGrid topic. As the doc specifies, this data is in the form of an Int8 [] so the only difference between the tutorial and my code is I replaced "String" with "Int8MultiArray"

I am running what I think is a fairly standard hector_mapping setup, and then I try and launch my subscriber node. The node launches fine and sits there forever, never receiving any messages. When I try rostopic list the topic is not there, despite the fact that the documentation for hector_mapping says that it publishes to this nav_msgs/OccupancyGrid topic.

It seems like I'm missing something to tell hector_mapping to publish, except that using rosrun map_server map_saver works perfectly, so clearly the data is there. What am I doing wrong?

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answered 2018-04-19 20:23:22 -0500

Troski gravatar image

nav_msgs/OccupancyGrid is not a topic, is a message type. the topic in the tutorial you point out is "/robot0/odom"

when you launch the packages in ros do in another console "rostopic list " ..... find the topic you like then do "rostopic info + <topic_name>" that will show you what kind of message the subscriber needs. then follow the tutorial and you should get your sub callback going.

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Asked: 2018-04-18 15:11:46 -0500

Seen: 71 times

Last updated: Apr 19 '18