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I am using slam_toolbox (in ROS Foxy) to generate a map of an environment using bag files of recorded laserScan and odometry data. The map is successfully generated, however, while running the node and visualising the sensor data (in frame 'cluod') on rviz, I get the following error,

Transform
No transform to fixed frame [map]. TF error: [Lookup would require extrapolation into the future. Requested time 1632836191.729568 but the latest data is at time 1631538428.177000, when looking up transform from frame [cloud] to frame [map]]

The fixed frame is set to 'map'.

Here is the tf_tree view from the tf2_tools view_frames.py program,

I interpret from the above image, that slam_toolbox is publishing the map->odom transformation with the current system timestamp, while the odom->base_link and base_link->cloud transforms have a past timestamp (from the time the bag was recorded) on them and it may be the cause of my issue.

I could not find any help on how to use slam_toolbox with recorded bag files and have also checked all the possible launch files in the slam-toolbox (e.g. offline, async, sync, etc). There was not much help to be found in the official documentation of slam_toolbox as well. Would be nice if anyone who's worked on a similar problem before, could help out with this.

The documentation everywhere suggest using the use_sim_time parameter to synchronize the output of the slam_toolbox to t

Yes, the timestamps are the same!

Hey, you are right. rosbag2 in foxy does not publish the clock. But even if you publish the clock, the foxy-devel distri

Mapping in slam_toolbox using bag files (ros2) I am using slam_toolbox (in ROS Foxy) to generate a map of an environment

Hi, I am a beginner in Python, Ros and Ubuntu and am having difficulties in running the first program on ROS, i.e. listener.py I am running Ros melodic in Ubuntu 18.04 The following error report comes up on running "rosrun hello_world listener.py"

joseph@joseph-Inspiron-5558:~$ rosrun hello_world talker.py 
Traceback (most recent call last):
  File "/home/joseph/catkin_ws/src/hello_world/scripts/talker.py", line 39, in <module>
    import rospy
  File "/opt/ros/melodic/lib/python2.7/dist-packages/rospy/__init__.py", line 47, in <module>
    from std_msgs.msg import Header
  File "/opt/ros/melodic/lib/python2.7/dist-packages/std_msgs/msg/__init__.py", line 1, in <module>
    from ._Bool import *
  File "/opt/ros/melodic/lib/python2.7/dist-packages/std_msgs/msg/_Bool.py", line 5, in <module>
    import genpy
  File "/opt/ros/melodic/lib/python2.7/dist-packages/genpy/__init__.py", line 34, in <module>
    from . message import Message, SerializationError, DeserializationError, MessageException, struct_I
  File "/opt/ros/melodic/lib/python2.7/dist-packages/genpy/message.py", line 44, in <module>
    import yaml
  File "/usr/lib/python2.7/dist-packages/yaml/__init__.py", line 2, in <module>
    from error import *
**ModuleNotFoundError: No module named 'error'**
Error in sys.excepthook:
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 53, in apport_excepthook
    if not enabled():
  File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 24, in enabled
    import re
  File "/usr/lib/python3.6/re.py", line 142, in <module>
    class RegexFlag(enum.IntFlag):
**AttributeError: module 'enum' has no attribute 'IntFlag'**

Original exception was:
Traceback (most recent call last):
  File "/home/joseph/catkin_ws/src/hello_world/scripts/talker.py", line 39, in <module>
    import rospy
  File "/opt/ros/melodic/lib/python2.7/dist-packages/rospy/__init__.py", line 47, in <module>
    from std_msgs.msg import Header
  File "/opt/ros/melodic/lib/python2.7/dist-packages/std_msgs/msg/__init__.py", line 1, in <module>
    from ._Bool import *
  File "/opt/ros/melodic/lib/python2.7/dist-packages/std_msgs/msg/_Bool.py", line 5, in <module>
    import genpy
  File "/opt/ros/melodic/lib/python2.7/dist-packages/genpy/__init__.py", line 34, in <module>
    from . message import Message, SerializationError, DeserializationError, MessageException, struct_I
  File "/opt/ros/melodic/lib/python2.7/dist-packages/genpy/message.py", line 44, in <module>
    import yaml
  File "/usr/lib/python2.7/dist-packages/yaml/__init__.py", line 2, in <module>
    from error import *
**ModuleNotFoundError: No module named 'error'**

The text in bold are the error messages and they seem to be something related to the version conflict in the multiple installations of python.

Any help in resolving this matter would be appreciated Thanks.

The issue has been resolved. I checked the script and it had "#!/usr/bin/env python3" in it, changing it to "#!/usr/bin/

ModuleNotFoundError: No module named 'error' Hi, I am a beginner in Python, Ros and Ubuntu and am having difficulties in