Need help to get coordinates from rviz running rplidar

asked 2019-11-07 13:02:55 -0500

Aarrick gravatar image

updated 2022-05-23 10:08:09 -0500

lucasw gravatar image

Hello everyone, I am running ROS Melodic on raspberry pi 4 (Debian). I have installed rplidar as well as Hector_Slam and both are running fine. I can view track my sensor as well as view the map in rviz now. The point is that I want to extract the coordinates of the points that are shown in rviz and use that to create my own map. I have tried using rosbag record to record the bag file. I run the roscore and open rviz and then play the bag file using rosbag play but the rviz does not show anything. I do not know if my bag file contains the data I need. I do not know how pointcloud, laserscan or pointcloud2 works in rviz. Could you please help me with this? I am stuck in this step for far too long. Thank you for your time. Much appreciate!

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What command did you use to record data to rosbag?

NAGALLA DEEPAK gravatar image NAGALLA DEEPAK  ( 2019-11-09 01:07:51 -0500 )edit

I used $ rosbag record -a to record everything. I tried using $ rosbag record /scan as well. Both didnt work.

Aarrick gravatar image Aarrick  ( 2019-11-09 01:19:00 -0500 )edit

Can you play your rosbag alone in one terminal and in a new terminal, enter $ rostopic list and see which topics have shown up?

NAGALLA DEEPAK gravatar image NAGALLA DEEPAK  ( 2019-11-09 01:24:13 -0500 )edit

This is what I see in the terminal while a bag file is playing: pi@raspberrypi:~ $ rostopic list /clock /initialpose /map /map_metadata /move_base_simple/goal /poseupdate /rosout /rosout_agg /scan /slam_cloud /slam_out_pose /tf /tf_static pi@raspberrypi:~ $

Aarrick gravatar image Aarrick  ( 2019-11-09 18:25:49 -0500 )edit

Is any data showing up when you do $ rostopic echo /scan other than 'NAN' or '0'? Also, how is your RPi being powered up?

NAGALLA DEEPAK gravatar image NAGALLA DEEPAK  ( 2019-11-09 23:20:20 -0500 )edit

A lot of data shows up while i use that code. Also, I am using 5v adapter to power my raspberry pi.

Aarrick gravatar image Aarrick  ( 2019-11-11 10:50:13 -0500 )edit

Can you share your ROS bag?

NAGALLA DEEPAK gravatar image NAGALLA DEEPAK  ( 2019-11-12 21:44:19 -0500 )edit

Deepak, sorry for the late reply. Here is the bag file.

Please help me extract coordinates of the points for each revolution.

Aarrick gravatar image Aarrick  ( 2019-11-15 10:50:37 -0500 )edit