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How to store explored nodes in ROS?

asked 2015-11-02 17:51:27 -0500

robo_explorer gravatar image


I am using nav2d to explore a map. Is there any way I can store the order of explored nodes in a data structure?

I was thinking we can whether I can use rosbag for this somehow. Please let me know if anyone knows about this


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What do you want to achieve? All nodes are published on a Marker topic, but this list is more or less unordered.

Sebastian Kasperski gravatar image Sebastian Kasperski  ( 2015-11-04 03:23:20 -0500 )edit

I want to check the overlap in the algorithm. So, I want to have the order of explored nodes, so that I can track what path the robot followed.

robo_explorer gravatar image robo_explorer  ( 2015-11-04 19:34:48 -0500 )edit

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answered 2015-11-05 02:48:26 -0500

Sebastian Kasperski gravatar image

I don't see how this could be done out-of-the-box. But the pointclouds that are attached to the nodes should have a sequence number or at least a timestamp, that can be used to order them. But you would have to find a proper way to output them via ROS.

Another way might be to wite a very simple node, that regularly logs to robot's pose via TF.

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Yes, that's a great idea, I can write a node to log the robot's pose through tf_listener. But, I am not sure, how can I trace the position back to the specific occupancy grid cell. Is there any way where I can relate a position with the cell number?

robo_explorer gravatar image robo_explorer  ( 2015-11-05 14:07:17 -0500 )edit

I don't think so. The grid map is dynamically created from the laser scans and the corrected poses from the slam-backend whenever get_map is called. Such a relation would even change with an optimization run of the backend after a loop was closed.

Sebastian Kasperski gravatar image Sebastian Kasperski  ( 2015-11-06 01:50:26 -0500 )edit

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Asked: 2015-11-02 17:51:27 -0500

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Last updated: Nov 05 '15