How to offset costmap in rviz?

Question

Hi there!

I'm running the examples found here: http://wiki.ros.org/rtabmap_ros/Tutorials/MappingAndNavigationOnTurtlebot

Now, I don't have a turtlebot, so my kinect is placed a lot higher up. This makes the map visualize pretty weird in rviz (it's floating in mid air).

How do I offset it to say 1m below it's current position on the z-axis?

Do I make a new frame with /base_link or similar as parent and edit a few launch files, if yes, what launch files? If no, how to move the map?

(Map position is uneditable in rviz)

Let me know if anything was unclear, thank you!

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Originally posted by TRyKKs on ROS Answers with karma: 1 on 2016-05-04

Post score: 0

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Original comments

Comment by Dox on 2018-07-20:
Hi! I have the same issue. Have you managed to solve it? I only have one static transform between base_link and camera_link. When I add another between base_link and ground I get and error that my tree is not connected.

Answer 1

Without modifying the robot state published by turtlebot launch file, you could add a static transform between the ground and base_footprint:

<node pkg="tf" type="static_transform_publisher" name="gound_to_base_tf" 
    args="0.0 0.0 1.0 0.0 0.0 0.0 /ground /base_footprint 100" />

You add this to demo_turtlebot_mapping.launch and change base_footprint by ground for rtabmap, rgbd_odometry and rtabmapviz nodes in the same launch file.

This way, the robot would be 1 meter over the ground, so lowering the map from 1 meter.

cheers

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Originally posted by matlabbe with karma: 6409 on 2016-05-04

This answer was ACCEPTED on the original site

Post score: 1

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Original comments

Comment by Dox on 2018-07-20:
I tried to follow your suggestion but with no success. This is how my transform tree looks with modifications. BTW, Odom is published by Rosaria and it connects to base_link.

Comment by matlabbe on 2018-07-23:
In your case, you cannot do the hack above on your robot, as odometry is already computed accordingly to base_link. You may try to make rossaria publishing odom to a base_footprint frame that would be on ground under base_link, then use base_footprint for rtabmap node.

Comment by Dox on 2018-07-25:
I did try that afterwards, but it seems like rosaria can only publish to base_link frame. I set base_link_frame parameter as base_footprint but I still get the same warning of two unconnected trees. There is no connection between odom --> base_footprint.

Comment by matlabbe on 2018-07-25:
well, in your tf tree, rossaria doesn't seem to publish any odometry