urdf/) |  [ Discussion
](https://discourse.articulatedrobotics.xyz/t/discussion-concept-design-urdf-
making-a-mobile-robot-pt-2/27)
3  |  [ Driving your virtual robot! ](https://youtu.be/IjFcr5r0nMs) |  22:57
|  [ Making a Mobile Robot #3 - Concept Design Gazebo
](https://articulatedrobotics.xyz/mobile-robot-3-concept-gazebo/) |  [
Discussion ](https://discourse.articulatedrobotics.xyz/t/discussion-concept-
design-gazebo-making-a-mobile-robot-pt-3/28)
4  |  [ Giving Our Robot a Brain - Raspberry Pi
](https://youtu.be/RAqFgU3Gfv0) |  06:59  |  [ Making a Mobile Robot #4 -
Raspberry Pi ](https://articulatedrobotics.xyz/mobile-robot-4-raspberry-pi/) |
[ Discussion ](https://discourse.articulatedrobotics.xyz/t/discussion-
raspberry-pi-robot-brain-making-a-mobile-robot-pt-4/29)
5  |  [ EVERYTHING you need to know about about robot power
](https://youtu.be/Iye4uVLmj8o) |  16:33  |  [ Making a Mobile Robot #5 -
Power Concepts ](https://articulatedrobotics.xyz/mobile-robot-5-power-theory/)
|  [ Discussion ](https://discourse.articulatedrobotics.xyz/t/discussion-
power-concepts-making-a-mobile-robot-pt-5/30)
6  |  [ Robot Power 2: Electric Boogaloo ](https://youtu.be/_FGYVgAti9M) |
14:04  |  No Blog post  |  [ Discussion
](https://discourse.articulatedrobotics.xyz/t/discussion-wiring-up-making-a-
mobile-robot-pt-6/31)
7  |  [ The Ultimate Guide to using Motors in Robotics (including ROS,
Raspberry Pi) ](https://youtu.be/-PCuDnpgiew) |  25:56  |  No Blog post  |  [
Discussion ](https://discourse.articulatedrobotics.xyz/t/discussion-motor-
guide-making-a-mobile-robot-pt-7/32)
8  |  [ How do we add LIDAR to a ROS robot? ](https://youtu.be/eJZXRncGaGM) |
22:45  |  [ Making a Mobile Robot #8 - Adding a Lidar
](https://articulatedrobotics.xyz/mobile-robot-8-lidar/) |  [ Discussion
](https://discourse.articulatedrobotics.xyz/t/discussion-adding-a-lidar-to-
our-robot-making-a-mobile-robot-pt-8/33)
9  |  [ How to use Cameras in ROS (Sim Camera and Pi Camera)
](https://youtu.be/A3nw2M47K50) |  32:01  |  [ Making a Mobile Robot #9 -
Adding a Camera ](https://articulatedrobotics.xyz/mobile-robot-9-camera/) |  [
Discussion ](https://discourse.articulatedrobotics.xyz/t/discussion-adding-a-
camera-to-our-robot-making-a-mobile-robot-pt-9/34)
10  |  [ How to get your robot to see in 3D! (Depth Cameras in ROS)
](https://youtu.be/T9xZ22i9-Ys?list=PLunhqkrRNRhYAffV8JDiFOatQXuU-NnxT) |
23:21  |  No blog post  |  [ Discussion
](https://discourse.articulatedrobotics.xyz/t/discussion-depth-cameras-and-


Powered by [ Discourse ](https://www.discourse.org) , best viewed with
JavaScript enabled


[ iRobot Roomba j7 (7150) Wi-Fi Connecte...
](https://www.amazon.com/dp/B094NW318F?amp;linkCode=ogi&th=1&psc=1&tag=robotbox0c-20)


Some posts may contain affiliate links. RobotBox.NET is a participant in the
Amazon Services LLC Associates Program, an affiliate advertising program.


![](https://robo-1249f.kxcdn.com/wp-content/themes/robotbox-theme/img/avatar-
df.png)


* [ GitHub Sponsors  Fund open source developers  ](/sponsors)


![Richard Harrison](https://robo-1249f.kxcdn.com/wp-content/themes/robotbox-
theme/img/5.jpg)


##  [ Packages  0  ](/orgs/iRobotEducation/packages?repo_name=create3_sim)


Cleaning System


The Create® 3 robot produces a fused odometry that combines its wheel
encoders, IMU, and ground optical flow sensor. The robot's coordinate system
is right-handed, with x forward, y left, and z up. It exposes this coordinate
system both through the tf tree and the ` /odom ` publication. The ` /tf `
tree from the robot exposes ROS 2 standard transforms ` odom->base_footprint `
and ` odom->base_link ` with corresponding definitions [ odom
](https://www.ros.org/reps/rep-0105.html#odom) , [ base_footprint
](https://www.ros.org/reps/rep-0120.html#base-footprint) , and [ base_link
](https://www.ros.org/reps/rep-0120.html#base-link) . ` base_link ` is defined
to be at the center of rotation of the robot with z height intersecting the
floor. ` base_footprint ` is the 2D planar representation ` base_link ` with
the pitch and roll factors removed from the transform, this can be useful for
applications like 2D planar mapping. The ` /odom ` publication contains the
same position and orientation as ` base_link ` in the form of a `
nav_msgs/msg/Odometry ` message with velocity additionally populated. Note:
the ` /odom ` -> ` /base_footprint ` and ` /odom ` -> ` base_link `
transformations can be disabled by setting the ` publish_odom_tfs ` parameter
to ` false ` . The ` publish_odom_tfs ` parameter cannot be set at runtime; it
must be configured from the [ ROS 2 parameters file on the application
configuration page ](../../webserver/application/#application-
ros-2-parameters-file) of the webserver, as it is loaded only at application
start.


brand new Genius Technology and PrecisionVision Navigation


[ irobot_create_gazebo
](/iRobotEducation/create3_sim/tree/main/irobot_create_gazebo
"irobot_create_gazebo")


Wifi Connected/App Control


[ View on Amazon
](https://www.amazon.com/dp/B094NYHTMF?amp;linkCode=ogi&th=1&psc=1&tag=robotbox0c-20
"View on Amazon")


####  Ignition Fortress


##  ROS 2 Topics


###  3\. Cleaning Test Results


> ⚠  ` create3_gazebo.launch.py ` should only be used once as it launches the
> Gazebo simulator itself. Additional robots should be spawned with `
> create3_spawn.launch.py ` . Namespaces and spawn points should be unique for
> each robot.


2210 mAh


ros2 launch irobot_create_gazebo_bringup create3_gazebo.launch.py x:=1.0 y:=0.5 yaw:=1.5707


#  [ iRobot Create 3 with Nav2 ](/t/irobot-create-3-with-nav2/34025)


##  About


Dustbin Capacity


Go to file


###  Is Roomba J7 a Good Robot Vacuum?


Reply


The spawn point can be changed with the ` x ` , ` y ` , ` z ` and ` yaw `
launch arguments:


###  Martha Sanchez


Last commit message


3 Likes


[ iRobot Roomba j6+ (6550) Self-Emptying...
](https://www.amazon.com/dp/B0BTTV2DYQ?amp;linkCode=ogi&th=1&psc=1&tag=robotbox0c-20)


[ ](https://twitter.com/iRobotEducation "twitter.com") [
](https://github.com/iRobotEducation "github.com") [
](https://www.facebook.com/iRobotEducation "www.facebook.com") [
](https://www.linkedin.com/company/irobot/ "www.linkedin.com")


    $ ros2 service list -t
    /e_stop [irobot_create_msgs/srv/EStop]
    /motion_control/describe_parameters [rcl_interfaces/srv/DescribeParameters]
    /motion_control/get_parameter_types [rcl_interfaces/srv/GetParameterTypes]
    /motion_control/get_parameters [rcl_interfaces/srv/GetParameters]
    /motion_control/list_parameters [rcl_interfaces/srv/ListParameters]
    /motion_control/set_parameters [rcl_interfaces/srv/SetParameters]
    /motion_control/set_parameters_atomically [rcl_interfaces/srv/SetParametersAtomically]
    /robot_power [irobot_create_msgs/srv/RobotPower]
    /robot_state/change_state [lifecycle_msgs/srv/ChangeState]
    /robot_state/get_available_states [lifecycle_msgs/srv/GetAvailableStates]
    /robot_state/get_available_transitions [lifecycle_msgs/srv/GetAvailableTransitions]
    /robot_state/get_state [lifecycle_msgs/srv/GetState]
    /robot_state/get_transition_graph [lifecycle_msgs/srv/GetAvailableTransitions]
    /static_transform/change_state [lifecycle_msgs/srv/ChangeState]
    /static_transform/describe_parameters [rcl_interfaces/srv/DescribeParameters]
    /static_transform/get_available_states [lifecycle_msgs/srv/GetAvailableStates]
    /static_transform/get_available_transitions [lifecycle_msgs/srv/GetAvailableTransitions]
    /static_transform/get_parameter_types [rcl_interfaces/srv/GetParameterTypes]
    /static_transform/get_parameters [rcl_interfaces/srv/GetParameters]
    /static_transform/get_state [lifecycle_msgs/srv/GetState]
    /static_transform/get_transition_graph [lifecycle_msgs/srv/GetAvailableTransitions]
    /static_transform/list_parameters [rcl_interfaces/srv/ListParameters]
    /static_transform/set_parameters [rcl_interfaces/srv/SetParameters]
    /static_transform/set_parameters_atomically [rcl_interfaces/srv/SetParametersAtomically]


[ iRobot Roomba j7 (7150)...
](https://www.amazon.com/dp/B094NW318F?tag=robotbox0c-20&linkCode=ogi&th=1&psc=1
"iRobot Roomba j7 \(7150\)...")


[ ![iRobot Roomba i7 vs iRobot Roomba j7](https://robo-1249f.kxcdn.com/wp-
content/uploads/2021/10/j7-vs-i7-compare.jpg)
](https://robotbox.net/roomba-j7-vs-i7-comparison-review/)


descr


[ ![iRobot Roomba j7+ \(7550\)...](https://m.media-
amazon.com/images/I/41+nRSV2JzL._SL160_.jpg)
](https://www.amazon.com/dp/B094NYHTMF?tag=robotbox0c-20&linkCode=ogi&th=1&psc=1
"iRobot Roomba j7+ \(7550\)...")


2210 mAh


  * ` /cmd_audio ` : use this topic to play specified notes from the robot speaker.
  * ` /cmd_lightring ` : use this topic to change the color of the light ring.
  * ` /cmd_vel ` : use this topic to command velocities in the robot reference frame.


We read every piece of feedback, and take your input very seriously.


That’s the end of this Roomba J7 vs. J7+ comparison review. As discussed
above, the two Roombas are all the same save for the fact that the Plus model
comes with extra accessories at a higher price. So at the end of the day, the
question is, do you want the extra accessories?


Hi, I’m Alberto from iRobot, one of the developers of the iRobot Create 3.


[ ros2 ](https://discourse.ros.org/tag/ros2) , [ simulation
](https://discourse.ros.org/tag/simulation) , [ hardware
](https://discourse.ros.org/tag/hardware)


3-4 hours


####  3 Reasons to Choose the Roomba J7+


Create® 3 can be spawned in the AWS small house in Gazebo and monitored
through RViz. This requires that the package ` aws_robomaker_small_house_world
` is available.


Charging Time


[ November 26, 2022 at 5:31 am
](https://robotbox.net/roomba-j7-vs-j7/#comment-47486)


    * [ Enterprise ](/enterprise)
    * [ Teams ](/team)
    * [ Startups ](/enterprise/startups)
    * [ Education  ](https://education.github.com)


|

View all files

##  Repository files navigation


Reply


Battery Capacity


**599.99 $** **238.2** $  **YOU SAVE: 361 $**


ros2 launch irobot_create_gazebo_bringup create3_gazebo.launch.py namespace:=my_robot


Cancel  Submit feedback


Color: **Black**


This repository contains packages for both the Classic and Ignition Gazebo
simulators:


[ Custom properties  ](/iRobotEducation/create3_sim/custom-properties)


|  21  |  2826  |  April 1, 2024

  * [ Home ](/)
  * [ Categories ](/categories)
  * [ FAQ/Guidelines ](/guidelines)
  * [ Terms of Service ](/tos)
  * [ Privacy Policy ](/privacy)


2. All trademarks mentioned are the property of their respective owners.  ↩


ROS 2 Simulation for the iRobot® Create® 3 Educational Robot


[ iRobot Roomba j7+ (7550) Self-Emptying...
](https://www.amazon.com/dp/B094NYHTMF?amp;linkCode=ogi&th=1&psc=1&tag=robotbox0c-20)


Yes. The Roomba J7 is a great choice if you are looking for the latest Roomba
on a budget. The J7 is a base model that works with the iRobot automatic self-
emptying bin technology though it doesn’t include the CleanBase unit. Buyers
can opt for the J7 at a lower cost and then upgrade by buying the CleanBase
unit separately.


Roomba j7 & Braava M6


  * ROS 2 Topics
  * ROS 2 Services
  * ROS 2 Actions
  * ROS 2 Parameters
  * ROS 2 Coordinate System


Name


ros2 launch irobot_create_ignition_bringup create3_ignition.launch.py namespace:=my_robot


    sudo apt-get update && sudo apt-get install wget
    sudo sh -c 'echo "deb http://packages.osrfoundation.org/gazebo/ubuntu-stable `lsb_release -cs` main" > /etc/apt/sources.list.d/gazebo-stable.list'
    wget http://packages.osrfoundation.org/gazebo.key -O - | sudo apt-key add -
    sudo apt-get update && sudo apt-get install ignition-fortress


##  ROS 2 Services


##  History


Important


###  License


###  6\. Smart Features and Convenience


[ ](https://www.facebook.com/Robotbox-215582315706796/) [
](https://www.reddit.com/user/RichardRB)


[ ![Roomba I6 vs J7 Comparison Review](https://robo-1249f.kxcdn.com/wp-
content/uploads/2022/01/i6-vs-j7.jpg) ](https://robotbox.net/roomba-i6-vs-j7/)


[ Check ALL Roomba DEALS ](https://amzn.to/3VVwVcQ)


#####  Namespacing


[ irobot_create_common
](/iRobotEducation/create3_sim/tree/main/irobot_create_common
"irobot_create_common")


[ March 22, 2023 at 4:29 pm
](https://robotbox.net/roomba-j7-vs-j7/#comment-52206)


![Roomba J7](https://robo-1249f.kxcdn.com/wp-
content/uploads/2021/10/roomba-j7-runtime.jpg)
The battery and runtime of a robot vacuum are very important as it determines
the size of floor the robot can clean on a single charge. As far as battery
and runtime are concerned, we will assess the battery technology used in the
J7 and J7+, battery capacity, runtime, and power management. So without
further ado, let’s get into it.


[ ![Image 'https://robo-1249f.kxcdn.com/wp-
content/uploads/2023/07/41MbbgsVIEL._SL160_.jpg'](https://robo-1249f.kxcdn.com/wp-
content/uploads/2023/07/41MbbgsVIEL._SL160_.jpg)
](https://www.amazon.com/dp/B0BCH3J9RD?amp;linkCode=ogi&th=1&psc=1&tag=robotbox0c-20)


Sorry for the long reply. Unfortunately, Roomba J7+ cannot run for as long as
6 hours. It can work for about 45 minutes up to one hour and a half, depending
on the mode and cleaning difficulty. Then, it needs to go back to its dock,
recharge, and after that, it starts from the same place it left off.
Recharging takes about an hour, and you won’t be able to find anything on the
market that can recharge as quickly as that.


Roomba j7+ (7550)


brand new Genius Technology and PrecisionVision Navigation


![](https://robo-1249f.kxcdn.com/wp-content/themes/robotbox-
theme/img/logo-f.png)


[ ](/iRobotEducation/create3_sim/commits/main/)

###


Reply


[ Report repository ](/contact/report-
content?content_url=https%3A%2F%2Fgithub.com%2FiRobotEducation%2Fcreate3_sim&report=iRobotEducation+%28user%29)


#  Provide feedback


![Roomba J7 Navigation and Mapping](https://robo-1249f.kxcdn.com/wp-
content/uploads/2021/10/roomba-j7-navigation.jpg)
One of the areas these two new Roombas excel in is navigation and mapping.


###  1\. Design and Aesthetics


Now, on to the main business of the day, how does the [ Roomba J7
](https://robotbox.net/compare/roomba-j6-vs-j7/) compare to the J7+. Well,
like earlier mentioned, these two Roombas are identical only that the plus
model comes with more accessories. Otherwise, they share all other features.


Subscribe to our email lists


![{{ config.title }}](https://robo-1249f.kxcdn.com/wp-content/themes/robotbox-
theme/img/logo.png)


Wifi Connected/App Control


Create® 3 can be spawned in an empty world in Gazebo and monitored through
RViz with:


[ LICENSE ](/iRobotEducation/create3_sim/blob/main/LICENSE "LICENSE")


Important


ros2 launch irobot_create_ignition_bringup create3_ignition.launch.py


  * [ Home ](../..)
  * Hardware  Hardware
    * [ Overview ](../../hw/overview/)
    * [ Mechanical ](../../hw/mechanical/)
    * Electrical  Electrical
      * [ Electrical Overview ](../../hw/electrical/)
      * [ Buttons and Light Ring ](../../hw/face/)
      * [ Adapter Board ](../../hw/adapter/)
    * Printable Accessories  Printable Accessories
      * [ Compute Boards ](../../hw/print_compute/)
      * [ Create® 3 Caster ](../../hw/print_casters/)
      * [ Generic Mounts ](../../hw/print_generic/)
      * [ Sensor Mounts ](../../hw/print_sensor_mounts/)
  * Webserver  Webserver
    * [ Overview ](../../webserver/overview/)
    * [ Home ](../../webserver/home/)
    * [ Connect ](../../webserver/connect/)
    * [ Update ](../../webserver/update/)
    * [ Logs ](../../webserver/logs/)
    * [ Application ](../../webserver/application/)
    * Beta Features  Beta Features
      * [ Serial Port Forward ](../../webserver/serial-config/)
      * [ Set Date and Time ](../../webserver/set-datetime/)
      * [ Edit ntp.conf ](../../webserver/edit-ntp-conf/)
      * [ Restart ntpd ](../../webserver/restart-ntpd/)
      * [ Set Wired Subnet ](../../webserver/set-wired-subnet/)
      * [ Override RMW Profile ](../../webserver/rmw-profile-override/)
      * [ Forget Wi-Fi Network ](../../webserver/forget-wifi/)
      * [ Override wpa_supplicant ](../../webserver/wpa-supp-override/)
    * [ About ](../../webserver/about/)
  * Setup  Setup
    * [ Connect to Wi-Fi ](../../setup/provision/)
    * [ Multi-Robot Setup ](../../setup/multi-robot/)
    * ROS 2 Setup  ROS 2 Setup
      * [ Galactic on Ubuntu 20 ](../../setup/ubuntu2004/)
      * [ Humble on Ubuntu 22 ](../../setup/ubuntu2204/)
      * [ Run with Docker ](../../setup/docker/)
      * [ Middleware Config ](../../setup/xml-config/)
      * [ Network Recommendations ](../../setup/network-config/)
    * Add a Compute Board  Add a Compute Board


[ iRobotEducation/create3_docs
](https://github.com/iRobotEducation/create3_docs "Go to repository")


##  [ Roomba J7+ (7550) ](https://www.amazon.com/iRobot-Roomba-Self-Emptying-
Vacuum-Identifies/dp/B094NYHTMF/?tag=robotbox0c-20)


###  Affiliate Disclosure


The Roomba J7+ is the ceiling model and was also released in September 2021.
This robot vacuum comes with the revamped iRobot CleanBase unit plus the
disposable bags, so it is ready for automatic self-emptying.


HEPA-style


#  Roomba j7 vs j7+: Is There Even a Difference?


The Roomba J7 Series is equipped with a **dual rubberized multi-surface
brushroll** that agitates and lifts dirt effectively. It is assisted by a side
sweeping brush that reaches dirt along wall edges and deep corners. Regardless
of the length of pet hair, the Roomba J7’s primary brush is resistant to
tangling. When it comes to vacuum power, the J7, despite being the latest
Roomba model, comes with an old motor that delivers 900pa at peak power.


[ 114 Commits  ](/iRobotEducation/create3_sim/commits/main/)


Interestingly, the J7 and J7+ come with a 0.5L onboard bin that can be emptied
automatically when the robot docks at the Clean Base® Automatic Dirt Disposal
unit. The J7+ comes with the Clean Base® Automatic Dirt Disposal unit and 2
dirt disposal bags. A single bag can hold up to a month’s dirt.


###  Swartzcop Kennedy


* Limited Time Deals


###  About


Repositories


ros2 launch irobot_create_gazebo_bringup create3_gazebo.launch.py


![](https://robo-1249f.kxcdn.com/wp-content/themes/robotbox-theme/img/avatar-
df.png)


Long story short, it is indeed possible to run SLAM using the sensing
capabilities provided by the Create 3, although we don’t recommend doing that
based on the IR sensors.


The best part about this robot vacuum is its performance when it comes to
handling pet messes.


[ .github ](/iRobotEducation/create3_sim/tree/main/.github ".github")


Multiple robots can be spawned with unique namespaces:


Have a look at the [ Create® 3 documentation
](https://iroboteducation.github.io/create3_docs/) for more details on the ROS
2 interfaces exposed by the robot.


[ Branches  ](/iRobotEducation/create3_sim/branches) [ Tags
](/iRobotEducation/create3_sim/tags)


**799.99 $** **569.99** $  **YOU SAVE: 230 $**


[ iRobot Roomba j7+ (7550)...
](https://www.amazon.com/dp/B094NYHTMF?tag=robotbox0c-20&linkCode=ogi&th=1&psc=1
"iRobot Roomba j7+ \(7550\)...")


[ SEE PRICE  – Amazon.com
](https://www.amazon.com/dp/B094NW318F/?tag=robotbox0c-20)


ROS 2 Simulation for the iRobot® Create® 3 Educational Robot


![Roomba J7 Smart Features and Convenience](https://robo-1249f.kxcdn.com/wp-
content/uploads/2021/10/roomba-j7-smart.jpg)
A good robot vacuum should be smart to allow for syncing with other connected
devices. Smart devices, including Roombas, also facilitate remote operation.


##  Roomba J7 vs. J7+: Our Verdict


Query


Navigation


[ February 1, 2023 at 6:32 pm
](https://robotbox.net/roomba-j7-vs-j7/#comment-50477)


Dual Multi Surface Rubber Brushes


3-4 hours


##  ROS 2 Actions


Battery Capacity


Mopping


##  Check Price


Just an F.Y.I. there are [ affiliate links in this post
](https://robotbox.net/affiliate-disclosure/) , and if you click any of those
links, we will earn a small commission.


[ View on Amazon
](https://www.amazon.com/dp/B0BTTV2DYQ?amp;linkCode=ogi&th=1&psc=1&tag=robotbox0c-20
"View on Amazon")


* Navigate to the workspace and install ROS 2 dependencies with:


![](https://robo-1249f.kxcdn.com/wp-content/themes/robotbox-theme/img/Richard-
foto.png)


Hi, everyone! I have recently bought iRobot Roomba and want advice. The manual
says it works very well on hard floors and carpets. Though I have a low-pile
carpet in my sitting room, I noticed that the machine does not work as
perfectly on it as I would like to see. I just don’t map this rug anymore and
clean it in an old-fashioned way – by hand. How can it be that it vacuums a
thick-pile carpet in my bedroom much better than that low-pile rug?


The question is crucial for such a big family as yours. However, the vacuum
cannot detect and avoid smaller items. it will push the socks around, suck in
charging cables if they are left loose on the floor, and they will stick in
the brushes, and shoe laces will also be caught and get rolled into the
brushes. Small paper scraps and receipts will get sucked up and clog the bin.
As for bigger objects, like pieces of linen, dog mats, jeans, shirts, or coats
on the floor, Roomba will push against them and then change its direction
completely. So, you will need to put all these things aside before the start
of the vacuum, or it may get out of order over time if all those trifles
continuously get sucked into it. Or purchasing a mechanical cleaner is better;
you will never have that sucking problem.


[ Check Price
](https://www.amazon.com/dp/B094NW318F?tag=robotbox0c-20&linkCode=ogi&th=1&psc=1
"Check Price")


##  Roomba Spring Deals 2024


Next is regarding the finish. The new J7 Series robot vacuums are silver on
black. There is a single control button and the iRobot logo at the top
interface.


Reply


![](https://robo-1249f.kxcdn.com/wp-content/themes/robotbox-theme/img/avatar-
df.png)


[ **49** forks ](/iRobotEducation/create3_sim/forks)


You can see the ROS 2 servers exposed by the Create® 3 robot running the `
ros2 service list ` command.


![Roomba J7 vs. J7+](https://robo-1249f.kxcdn.com/wp-
content/uploads/2021/10/j7-design.jpg)
The first talking point in this Roomba J7 vs. J7+ comparison review is the
design and aesthetics. Here, we will look at the robot’s shape, diameter,
height, and finish. So let’s get into it.


  1. [ ROS 2 humble ](https://docs.ros.org/en/humble/Installation/Ubuntu-Install-Debians.html)
  2. ROS 2 dev tools:
    * [ colcon-common-extensions ](https://pypi.org/project/colcon-common-extensions/)
    * [ rosdep ](https://pypi.org/project/rosdep/) : Used to install dependencies when building from sources
    * [ vcs ](https://pypi.org/project/vcstool/) : Automates cloning of git repositories declared on a YAML file.


    $ ros2 topic list -t
    /battery_state [sensor_msgs/msg/BatteryState]
    /cliff_intensity [irobot_create_msgs/msg/IrIntensityVector]
    /cmd_audio [irobot_create_msgs/msg/AudioNoteVector]
    /cmd_lightring [irobot_create_msgs/msg/LightringLeds]
    /cmd_vel [geometry_msgs/msg/Twist]
    /dock_status [irobot_create_msgs/msg/DockStatus]
    /hazard_detection [irobot_create_msgs/msg/HazardDetectionVector]
    /imu [sensor_msgs/msg/Imu]
    /interface_buttons [irobot_create_msgs/msg/InterfaceButtons]
    /ir_intensity [irobot_create_msgs/msg/IrIntensityVector]
    /ir_opcode [irobot_create_msgs/msg/IrOpcode]
    /kidnap_status [irobot_create_msgs/msg/KidnapStatus]
    /mouse [irobot_create_msgs/msg/Mouse]
    /odom [nav_msgs/msg/Odometry]
    /parameter_events [rcl_interfaces/msg/ParameterEvent]
    /rosout [rcl_interfaces/msg/Log]
    /slip_status [irobot_create_msgs/msg/SlipStatus]
    /stop_status [irobot_create_msgs/msg/StopStatus]
    /tf [tf2_msgs/msg/TFMessage]
    /tf_static [tf2_msgs/msg/TFMessage]
    /wheel_status [irobot_create_msgs/msg/WheelStatus]
    /wheel_ticks [irobot_create_msgs/msg/WheelTicks]
    /wheel_vels [irobot_create_msgs/msg/WheelVels]


Notably, the J7+ comes with the iRobot CleanBase unit, so homeowners don’t
have to worry about emptying the bin after every cleaning session.


[ .gitignore ](/iRobotEducation/create3_sim/blob/main/.gitignore ".gitignore")


    * ` irobot_create_gazebo_bringup ` Launch files and configurations
    * ` irobot_create_gazebo_plugins ` Sensor plugins
    * ` irobot_create_gazebo_sim ` Metapackage
  * ` irobot_create_ignition ` Packages used for the Ignition Gazebo Simulator


HEPA-style


[ ![iRobot Roomba j7+ \(7550\)...](https://m.media-
amazon.com/images/I/41+nRSV2JzL._SL160_.jpg)
](https://www.amazon.com/dp/B094NYHTMF?tag=robotbox0c-20&linkCode=ogi&th=1&psc=1
"iRobot Roomba j7+ \(7550\)...")


For more details on how to use these actions, please have a look at their
corresponding sections.


* Limited Time Deals


#####  Namespacing


Multiple robots can be spawned with unique namespaces:


|  10  |  6178  |  December 6, 2016
[ Upgrading Turtlebot3 with better LIDAR
](https://discourse.ros.org/t/upgrading-turtlebot3-with-better-lidar/6603)


###  Laura MacGregor


![Roomba J7 vs. J7+](https://robo-1249f.kxcdn.com/wp-
content/uploads/2023/06/roomba-j7-vs-j7plus.jpg)


[ **97** stars ](/iRobotEducation/create3_sim/stargazers)


Name  |  Name  |


Author: [ Richard Harrison  ](https://robotbox.net/author/richard/)


[ ![Image 'https://robo-1249f.kxcdn.com/wp-content/uploads/2023/07/41h0AnG-
IYL._SL160_.jpg'](https://robo-1249f.kxcdn.com/wp-
content/uploads/2023/07/41h0AnG-IYL._SL160_.jpg)
](https://www.amazon.com/dp/B0BTTV2DYQ?amp;linkCode=ogi&th=1&psc=1&tag=robotbox0c-20)


Auto Dirt Disposal


[ ![iRobot Roomba j7 \(7150\)...](https://m.media-
amazon.com/images/I/41EViZ5Kt3L._SL160_.jpg)
](https://www.amazon.com/dp/B094NW318F?tag=robotbox0c-20&linkCode=ogi&th=1&psc=1
"iRobot Roomba j7 \(7150\)...")


  * [ ![@alsora](https://avatars.githubusercontent.com/u/25433200?s=64&v=4) ](https://github.com/alsora)
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* [ The ReadME Project  GitHub community articles  ](/readme)


[ ](https://github.com/)


Voice control


[ irobot_create_common
](/iRobotEducation/create3_sim/tree/main/irobot_create_common
"irobot_create_common")


Resources


* [ Pricing ](/pricing)


[ ![Image 'https://robo-1249f.kxcdn.com/wp-
content/uploads/2023/07/51X6WX5Ju4L._SL160_.jpg'](https://robo-1249f.kxcdn.com/wp-
content/uploads/2023/07/51X6WX5Ju4L._SL160_.jpg)
](https://www.amazon.com/dp/B094NYHTMF?amp;linkCode=ogi&th=1&psc=1&tag=robotbox0c-20)


Explore


[ ](https://github.com "GitHub") © 2024 GitHub, Inc.


This is a ROS 2 simulation stack for the [ iRobot® Create® 3
](https://edu.irobot.com/create3) robot. Both Ignition Gazebo and Classic
Gazebo are supported.


[ Navigation Stack  ](/c/navigation/44)


    export IGNITION_VERSION=fortress
    colcon build --symlink-install
    source install/local_setup.bash


When it comes to power management, the Roomba J series robot vacuums will
automatically dock on the charging base once the battery levels go down. The
recharge time is 2-3 hours. After recharging, the robot will resume cleaning
without being prompted. All this is courtesy of iRobot’s patented smart
recharge and resume technology.


    $ ros2 action list -t
    /audio_note_sequence [irobot_create_msgs/action/AudioNoteSequence]
    /dock [irobot_create_msgs/action/Dock]
    /drive_arc [irobot_create_msgs/action/DriveArc]
    /drive_distance [irobot_create_msgs/action/DriveDistance]
    /led_animation [irobot_create_msgs/action/LedAnimation]
    /navigate_to_position [irobot_create_msgs/action/NavigateToPosition]
    /rotate_angle [irobot_create_msgs/action/RotateAngle]
    /undock [irobot_create_msgs/action/Undock]
    /wall_follow [irobot_create_msgs/action/WallFollow]


For the record, the Roomba J7 uses a different Clean Base unit. It is shorter
and wider and boasts a sleek design compared to the original CleanBase unit
that the other self-emptying Roombas use. It also has a clever compartment for
keeping the extra bags.


##  [ Contributors  15  ](/iRobotEducation/create3_sim/graphs/contributors)


Wifi Connected/App Control


HEPA-style


Additional navigation options


iRobot equips the two robot vacuums with a Roomba® i8 Denali 2210mAh battery,
the same one used in the Roomba i8. This battery can offer a cool 90 minutes
runtime which is enough juice to vacuum a small to medium-sized apartment on a
single charge.


` -l NUM ` , ` --limit=NUM `


#  Download or record a bag file


` rosbag info ` displays a human-readable summary of the contents of the bag
files, including start and end times, topics with their types, message counts
and median frequency, and compression statistics.


* Use the UDP transport hint when subscribing to topics


    $ rosbag info foo.bag
    path:        foo.bag
    version:     2.0
    duration:    1.2s
    start:       Jun 17 2010 14:24:58.83 (1276809898.83)
    end:         Jun 17 2010 14:25:00.01 (1276809900.01)
    size:        14.2 KB
    messages:    119
    compression: none [1/1 chunks]
    types:       geometry_msgs/Point [4a842b65f413084dc2b10fb484ea7f17]
    topics:      /points   119 msgs @ 100.0 Hz : geometry_msgs/Point


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` --node=NODE `


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[ ![tryan gravatar
image](//www.gravatar.com/avatar/4cd1a4a3c51b6947acbcfb58c7f1f988?s=16&d=identicon&r=PG)
](/users/33908/tryan/) [ tryan ](/users/33908/tryan/) (  2021-03-25 09:56:19
-0500  )  edit


This is the current list of supported ` rosbag ` subcommands:


##  rosbag decompress


Rows of the ` BagSelection ` or ` rosbagreader ` object, specified as an _n_
-element vector, where _n_ is the number of rows to retrieve messages from.
Each entry in the vector corresponds to a numbered message in the bag. The
range of the rows is [1, ` bag.NumMessage ` ].


_Note that in any of the commands below, the` time ` command is prepended
simply because it will print out how long each command takes, and since
sometimes these commands can take a long time, it is useful to use the ` time
` command to gain an idea of how long a given command should take. If you
don't want to use it, you may remove the ` time ` part of any of the commands
below. _


    * Use BZ2 compression. See [ compress ](/rosbag/Commandline#compress) for details.

                $ rosbag record -j /chatter


  * ` filter <in-bag> <out-bag> <expression> `
    * Convert a bag file using the given Python expression.

                $ rosbag filter my.bag only-tf.bag "topic == '/tf'"


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  * [ rosbag ](/rosbag)
  * [ Commandline ](/rosbag/Commandline)


##  rosbag fix


Sort by »  [ oldest  ](/question/374115/python-api-rosbag-write-custom-
message/?sort=oldest#sort-top) [ newest  ](/question/374115/python-api-rosbag-
write-custom-message/?sort=latest#sort-top) [ most voted
](/question/374115/python-api-rosbag-write-custom-message/?sort=votes#sort-
top)


To read the same messages shown in Option 1 above, use:


  * Help Center
  * MathWorks


###  ` rows ` —  Rows of ` BagSelection ` or ` rosbagreader ` object
_n_ -element vector


##  Description


    * Show the usage and exit.

                $ rosbag info -h


` -x EXCLUDE_REGEX ` , ` --exclude=EXCLUDE=REGEX `


Optionally, to see "progress" by watching the yaml file grow in size, in a new
terminal, run the following. Note: the yaml text file will be about 2x as
large as the original binary .bag file when complete.


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    * Show the usage and exit.

                $ rosbag fix -h


` -h ` , ` --help `


bSel = select(bag,'Topic','/turtle1/pose');


You can also create messages as structures directly, but make sure to specify
the data format as ` "struct" ` for the publisher, subscriber, or other ROS
objects as well. ROS objects still use message objects by default.


  * ` --clock `
    * Publish the clock time

                $ rosbag play --clock recorded1.bag


_Note that topics.yaml is a true YAML-formatted file. All non-YAML content,
such as message separators, is commented out with the` # ` symbol. _


    * Split bag at most MAX_SPLITS times, then begin deleting the oldest files. This creates a fixed size or duration recording.

                $ rosbag record --split --size 1024 --max-splits 3 /chatter
        $ rosbag record --split --duration 10m --max-splits 6 /chatter


  * ` compress <bag-files> `
    * Compress the given bag files using BZ2.

                $ rosbag compress *.bag


` rosbag play ` reads the contents of one or more bag file, and plays them
back in a time-synchronized fashion. Time synchronization occurs based on the
global timestamps at which messages were received. Playing will begin
immediately, and then future messages will be published according to the
relative offset times. If two separate bag files are used, they are treated as
a single bag with interlaced times according to the timestamps. This means if
you record one bag, wait an hour, and record a second bag, when you play them
back together you will have an hour-long dead period in the middle of your
playback.


[ ![Asdewar gravatar image](/m/default/media/images/nophoto.png?v=28)
](/users/71807/asdewar/)


        $ time rosbag play --immediate demo.bag --topics /obs1/gps/fix /diagnostics_agg
    [ INFO] [1591916465.758724557]: Opening demo.bag

    Waiting 0.2 seconds after advertising topics... done.

    Hit space to toggle paused, or 's' to step.
     [RUNNING]  Bag Time: 1490150297.770734   Duration: 19.703405 / 19.703405
    Done.

    real  0m1.570s
    user  0m0.663s
    sys 0m0.394s


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add a comment


[ Publish to topic from file ](/question/221828/publish-to-topic-from-file/)


Python API rosbag write custom message


Toggle Main Navigation


  1. Download and install [ `ros_readbag.py` ](https://github.com/ElectricRCAircraftGuy/eRCaGuy_dotfiles/blob/master/useful_scripts/ros_readbagfile.py) using these commands. Be sure to read the comments in the top of the file for the latest information on installation instructions and python dependencies.

        # Download the file
    wget https://raw.githubusercontent.com/ElectricRCAircraftGuy/eRCaGuy_dotfiles/master/useful_scripts/ros_readbagfile.py
    # Make it executable
    chmod +x ros_readbagfile.py
    # Ensure you have the ~/bin directory for personal binaries
    mkdir -p ~/bin
    # Move this executable script into that directory as `ros_readbagfile`, so that it will
    # be available as that command
    mv ros_readbagfile.py ~/bin/ros_readbagfile
    # Re-source your ~/.profile file to ensure ~/bin is in your PATH, so you can use this
    # new `ros_readbagfile` command you just installed
    # Note: this assumes you are on Linux Ubuntu with a default `~/.profile` file. If you're
    # on some other Linux distribution, such as Arch Linux, you can manually create the
    # `~/.profile` file. See here for details:
    # https://answers.ros.org/question/371583/ros_readbagfile-command-not-found/?answer=403354#post-id-403354
    . ~/.profile
    #
    # Install python dependencies (see the comments at the top of the ros_readbagfile.py
    # file for the latest dependencies and instructions)
    pip install bagpy
    pip3 install bagpy


` m `


#  Why use `ros_readbagfile` for this purpose instead of `rostopic echo -b`?


* [ Get MATLAB ](https://login.mathworks.com/embedded-login/landing.html?cid=getmatlab&s_tid=gn_getml)


time rg 'key: "piksi_' topics.yaml | sort -V | awk '!seen[$0]++'


Search Help Center


    * Prepend PREFIX to beginning of bag name before date stamp.

                $ rosbag record -o session1 /chatter


    * Show the usage and exit.

                $ rosbag check -h


[ tryan ](/users/33908/tryan/)
1421  ●  96  ●  26


[ none ](/questions/scope:all/sort:activity-desc/tags:none/page:1/) ×


* [ rosbag ](/questions/scope:all/sort:activity-desc/tags:rosbag/page:1/)


[ edit ](/questions/374115/edit/) [ retag ](/s/questions/374115/retag/) flag
offensive  [ close ](/questions/374115/close/) merge  delete


` msgs = readMessages(  ___  ,"DataFormat",Format)  `


Source: [ this material was adapted from instructions first published in this
document here
](https://github.com/ElectricRCAircraftGuy/eRCaGuy_dotfiles/blob/master/git%20%26%20Linux%20cmds%2C%20help%2C%20tips%20%26%20tricks%20-%20Gabriel.txt)
, and [ the Python script is from here: ros_readbag.py
](https://github.com/ElectricRCAircraftGuy/eRCaGuy_dotfiles/blob/master/useful_scripts/ros_readbagfile.py)
.


  1. You need to know the _exact_ topic names you'd like to read from the bag file. So, let's see what's in the bag file. In any terminal, manually inspect all published topics and how many messages were published to each topic with this command:

        time rosbag info demo.bag
    # OR (if you know part of the topic names of interest before-hand):
    time rosbag info mybag.bag | grep -E "(topic1|topic2|topic3)"


_Note that the following examples require the ripgrep (` rg ` ) command, which
is like ` grep ` only waaay faster. See here: [
https://github.com/BurntSushi/ripgrep#installation
](https://github.com/BurntSushi/ripgrep#installation) . Install ripgrep ( ` rg
` ) with:


  * ` -k ` , ` --keep-alive `
    * Keep alive past end of bag (useful for publishing latched topics).

                $ rosbag play -k recorded1.bag


To output a machine-readable representation, use ` --yaml ` . See the [
cookbook ](/rosbag/Cookbook#get_summary_information) for an example of how to
load this representation in code.


` -f ` , ` --force `


Note: you can kill any running processes. No ` roscore ` , for instance, is
required.


Select a specific topic.


**IMPORTANT:** This wiki page quickly goes out-of-date. To ensure you are
fully aware of all command-line options available in your version of ROS,
simply run ` rosbag -h ` to see what subcommands are available for the `
rosbag ` command, then run ` rosbag <subcommand> -h ` to see what options are
available for a given subcommand. Ex: ` rosbag play -h ` will show you the
most up-to-date list of all options available for your installation for the `
rosbag play ` subcommand.


        $ rostopic echo /diagnostics_agg | tee topic2.yaml
    WARNING: topic [/diagnostics_agg] does not appear to be published yet


Use ` cellfun ` to extract all the ` X ` and ` Y ` fields from the structure.
These fields represent the  _xy_ positions of the robot during the rosbag
recording.


The ROS Wiki is for ROS 1. Are you using ROS 2 ( [ Humble
](http://docs.ros.org/en/humble/) , [ Iron ](http://docs.ros.org/en/iron/) ,
or [ Rolling ](http://docs.ros.org/en/rolling/) )?
[ Check out the ROS 2 Project Documentation ](http://docs.ros.org)
Package specific documentation can be found on [ index.ros.org
](https://index.ros.org)


The Python expression can access any of the Python builtins plus:


  3. Now use ` ros_readbagfile ` . The general format is:

        # read these topics and print them to stdout
    time ros_readbagfile <mybagfile.bag> [topic1] [topic2] [topic3] [...]

    # Write to the topics.yaml file withOUT also printing to stdout
    time ros_readbagfile <mybagfile.bag> [topic1] [topic2] [topic3] [...] > topics.yaml

    # OR (preferred, so you can easily see it is still running): write to the
    # topics.yaml file AND print to stdout
    time ros_readbagfile <mybagfile.bag> [topic1] [topic2] [topic3] [...] | tee topics.yaml


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` rosbag compress ` is a command-line tool for compressing bag files.


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Let's say you want to find a list of all key entries which begin with
"piksi_". You can do so by searching for the string " ` key: "piksi_ ` ", as
follows.


    msgStructs = readMessages(bSel,'DataFormat','struct');
    msgStructs{1}

    ans = _struct with fields:_
            MessageType: 'turtlesim/Pose'
                      X: 5.5016
                      Y: 6.3965
                  Theta: 4.5377
         LinearVelocity: 1
        AngularVelocity: 0


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#  Option 2: use the ros_readbagfile script to easily extract the topics of
interest


You must specify ` "DataFormat","struct" ` in the function to get messages as
a cell array of structures. Using structures can be significantly faster than
using message objects, and custom message data can be read directly without
loading message definitions using [ ` rosgenmsg ` ](rosgenmsg.html) .


    * Suppress noncritical messages.

                $ rosbag reindex -q *.bag


The bag format supports interleaving compressed data chunks with uncompressed
chunks in a single bag. Running ` rosbag compress ` on a bag with compressed
data chunks will decompress and compress the bag using the specified
compression format.


You can also select a web site from the following list:


    * Show the usage and exit.

                $ rosbag compress -h


Now that you have the .yaml file (produced from the .bag file), here are some
demonstrations of how to scan it for a list of keys or text strings you are
interested in to see if certain data is present.


[ Open Live Script
](matlab:openExample\('ros/ReturnROSMessagesAsACellArrayROSExample'\))


To use ROS messages as structures, use the ` "DataFormat" ` name-value
argument when creating your publishers, subscribers, or other ROS objects. Any
messages generated from these objects will utilize structures.


[ **asked 2021-03-16 15:14:04 -0500  ** ](/questions/374115/revisions/)


[ ![Asdewar gravatar image](/m/default/media/images/nophoto.png?v=28)
](/users/71807/asdewar/) [ Asdewar ](/users/71807/asdewar/) (  2021-03-25
09:31:28 -0500  )  edit


` rosbag record ` subscribes to topics and writes a bag file with the contents
of all messages published on those topics. The file contains interlaced,
serialized ROS messages dumped directly to a single file as they come in over
the wire. This is the most performance and disk-friendly recording format
possible. To further reduce disk usage, you can compress bag files as they are
created.


##  Friends And Related Function Documentation
##  ◆  View
|  friend class [ View ](classrosbag_1_1View.html)
---
friend

Definition at line [ 93 ](message__instance_8h_source.html#l00093) of file [
message_instance.h ](message__instance_8h_source.html) .
##  Member Data Documentation
##  ◆  bag_
|  [ Bag ](classrosbag_1_1Bag.html) const* rosbag::MessageInstance::bag_
---
private

Definition at line [ 133 ](message__instance_8h_source.html#l00133) of file [
message_instance.h ](message__instance_8h_source.html) .
##  ◆  connection_info_
|  [ ConnectionInfo ](structrosbag_1_1ConnectionInfo.html) const*
rosbag::MessageInstance::connection_info_
---
private

Definition at line [ 131 ](message__instance_8h_source.html#l00131) of file [
message_instance.h ](message__instance_8h_source.html) .
##  ◆  index_entry_
|  const [ IndexEntry ](structrosbag_1_1IndexEntry.html)
rosbag::MessageInstance::index_entry_
---
private


  * ` --queue=SIZE `
    * Use an outgoing queue of size SIZE (defaults to 0. As of **1.3.3** defaults to 100).

                $ rosbag play --queue=1000 recorded1.bag


Probably not, what do you mean? I have to install it like a python module? I
only have that .msg file but I did not know that it could be installed.


ROS Resources: [ Documentation ](http://wiki.ros.org/) | [ Support
](http://wiki.ros.org/Support) | [ Discussion Forum
](http://discourse.ros.org/) | [ Index ](http://index.ros.org/) | [ Service
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Open Mobile Search


Create a ` rosbagreader ` object of all the messages in the rosbag log file.


###  Americas


  * Documentation
  * [ Examples ](../examples.html?category=ros-bag-file-logging-and-analysis&s_tid=CRUX_topnav)
  * [ Functions ](../referencelist.html?type=function&category=ros-bag-file-logging-and-analysis&s_tid=CRUX_topnav)
  * [ Blocks ](../referencelist.html?type=block&category=ros-bag-file-logging-and-analysis&s_tid=CRUX_topnav)
  * [ Apps ](../referencelist.html?type=app&category=ros-bag-file-logging-and-analysis&s_tid=CRUX_topnav)
  * [ Videos ](/support/search.html?fq\[\]=asset_type_name:video%20category:ros/ros-bag-file-logging-and-analysis&s_tid=CRUX_topnav)
  * [ Answers ](/support/search.html?fq\[\]=asset_type_name:answer%20category:ros/ros-bag-file-logging-and-analysis&s_tid=CRUX_topnav)


A backup of each bag file (with the extension ` .orig.bag ` ) is made before
the bag is decompressed. If the backup file already exists (and the ` -f `
option isn't specified) then the tool will not decompress the file.


See more instructions and usage examples on the [ rosbag migration page
](/rosbag/migration) .


time ros_readbagfile large_bag_file.bag /topic1


  * ` fix <in-bag> <out-bag> [rules.bmr] `
    * Repairs a bag using registered rules (and optionally locally defined rules).

                $ rosbag fix old.bag repaired.bag myrules.bmr


Contents


    * Show the usage and exit.

                $ rosbag record -h


` -h ` , ` --help `


##  rosbag filter


It can record a bag, republish the messages from one or more bags, summarize
the contents of a bag, check a bag's message definitions, filter a bag's
messages based on a Python expression, compress and decompress a bag and
rebuild a bag's index.


firstMsgs = readMessages(bagselect2,1:10);


##  1  Answer


[ collapse all ](javascript:void\(0\);)


Select the China site (in Chinese or English) for best site performance. Other
MathWorks country sites are not optimized for visits from your location.


  * [ Distributions ](/Distributions)
  * [ ROS/Installation ](/ROS/Installation)
  * [ ROS/Tutorials ](/ROS/Tutorials)
  * [ RecentChanges ](/RecentChanges)
  * [ reading msg... a bag file ](/rosbag/Tutorials/reading%20msgs%20from%20a%20bag%20file)


The output should match the message definition:


    * Show the usage and exit.

                $ rosbag reindex -h


To filter based on time, convert the time to a floating point number (use UNIX
time, to get this value, use rosbag info):


[ edit ](/s/answers/374173/edit/) flag offensive  delete  [ link
](/question/374115/python-api-rosbag-write-custom-message/?answer=374173#post-
id-374173 "permanent link") more


edit


#  See Also:


#  rosbag command-line tool:


allMsgs = readMessages(bagselect2);


` -o PREFIX ` , ` --output-prefix=PREFIX `


  * [ play ](/rosbag/Commandline#play)
    * Play back the contents of one or more bag files.


    * Generate a bag migration rule file named RULEFILE.

                $ rosbag check -g diagnostics.bmr diag.bag


Contact your local office


` --split `


_Since R2019b_


Note that newly published topics are discovered by periodically polling the
master. ` rosbag record -a ` will likely miss initial messages published on
any topic.


](../../../../api/roscpp_traits/html/classboost_1_1shared__ptr.html) < T > |
[ instantiate
](classrosbag_1_1MessageInstance.html#a369b32708a1a8bdaad133a47152a4885) ()
const
|  Templated call to instantiate a message. [ More...
](classrosbag_1_1MessageInstance.html#a369b32708a1a8bdaad133a47152a4885)

bool  |  [ isLatching
](classrosbag_1_1MessageInstance.html#a26d1fd480ea164f60329c3225efcb390) ()
const
template<class T >
bool  |  [ isType
](classrosbag_1_1MessageInstance.html#a5f3d1284f027c2563cecf7b978207783) ()
const
|  Test whether the underlying message of the specified type. [ More...
](classrosbag_1_1MessageInstance.html#a5f3d1284f027c2563cecf7b978207783)

uint32_t  |  [ size
](classrosbag_1_1MessageInstance.html#a5184e1aa20069f04edbf4fdf9ad98638) ()
const
|  Size of serialized message. [ More...
](classrosbag_1_1MessageInstance.html#a5184e1aa20069f04edbf4fdf9ad98638)

template<typename Stream >
void  |  [ write
](classrosbag_1_1MessageInstance.html#a0bad9d854247962b081c04c0ee2071b4) ( [
Stream ](classrosbag_1_1Stream.html) &stream) const
|  Write serialized message contents out to a stream. [ More...
](classrosbag_1_1MessageInstance.html#a0bad9d854247962b081c04c0ee2071b4)

##  Private Member Functions

---
|  [ MessageInstance
](classrosbag_1_1MessageInstance.html#a9f9dcd12645def9105d8d53afa8921ae) ( [
ConnectionInfo ](structrosbag_1_1ConnectionInfo.html) const *connection_info,
[ IndexEntry ](structrosbag_1_1IndexEntry.html) const &index, [ Bag
](classrosbag_1_1Bag.html) const &bag)


  * [ Switzerland (English) ](https://ch.mathworks.com)
  * [ Switzerland (Deutsch) ](https://ch.mathworks.com)
  * [ Switzerland (Français) ](https://ch.mathworks.com)


#  readMessages


Seen: **2,105 times**


##  Syntax


[ ROS Melodic OpenCV xfeatures2d ](/question/312669/ros-melodic-opencv-
xfeatures2d/)


* the message


  3. Open up another terminal. Note: to open up another terminal tab in the same terminal window you can use **Ctrl + Shift + T** on Ubuntu. Subscribe to the ` /obs1/gps/fix ` topic, echoing (printing) everything published on this topic, while also ` tee ` ing it to a file for later review, all in yaml format:

        rostopic echo /obs1/gps/fix | tee topic1.yaml


* [ Documentation Home  ](../../index.html?s_tid=CRUX_lftnav)


A backup of each bag file (with the extension ` .orig.bag ` ) is made before
the bag is reindexed. If the backup file already exists (and the ` -f ` option
isn't specified) then the tool will not reindex the file.


                key: "Early diagnostic update count:"
            value: "0"
          -
            key: "Zero seen diagnostic update count:"
            value: "0"

    # =======================================
    # topic:           /obs1/gps/fix
    # msg_count:       30
    # timestamp (sec): 1490150297.770734310
    # - - -
    header:
      seq: 4028
      stamp:
        secs: 1490150297
        nsecs: 744347249
      frame_id: "gps"
    status:
      status: 0
      service: 1
    latitude: 37.40075654660259
    longitude: -122.10815948235131
    altitude: -6.351304670230949
    position_covariance: [1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0]
    position_covariance_type: 0

    # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    # Total messages found:               70
    #
    #    /diagnostics_agg:                40
    #    /obs1/gps/fix:                   30
    #
    # DONE.
    # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    real    0m0.812s
    user    0m0.599s
    sys 0m0.077s


  * ` --try-future-version `
    * still try to open a bag file, even if the version number is not known to the player


Except where otherwise noted, the ROS wiki is licensed under the
[ Creative Commons Attribution 3.0
](http://creativecommons.org/licenses/by/3.0/)


Its because I want to make a bridge beetween a rosbag file and a txt file, and
the only way I know to write in the bag file is to use the rosbag API for
python


2 followers


END.


The site is read-only. Please transition to use Robotics Stack Exchange


[ ` select ` ](select.html) |  [ ` rosbag ` ](rosbag.html) |  [ ` timeseries `
](timeseries.html) |  [ ` rosbagreader ` ](rosbagreader.html)


` --output-dir=DIR `


[ collapse all ](javascript:void\(0\);)


` -p ` , ` --publish ` New in ROS Melodic


` --print=PRINT-EXPRESSION `


###  ` bag ` —  Index of messages in rosbag
` BagSelection ` object  |  ` rosbagreader ` object


        $ rostopic echo /obs1/gps/fix | tee topic1.yaml
    WARNING: topic [/obs1/gps/fix] does not appear to be published yet


` t `


##  Stats


##  Input Arguments


Search MathWorks.com


` -d ` , ` --duration `


###  R2021a:  ROS Message Structures


Here is the command to run:


#  Page


  * [ ROS Toolbox ](../index.html?s_tid=CRUX_lftnav)
  * [ Bag File Logging and Analysis  ](../ros-bag-file-analysis.html?s_tid=CRUX_lftnav)
  * [ ROS Bag File Logging and Analysis  ](../ros-bag-file-logging-and-analysis.html?s_tid=CRUX_lftnav)


Using structures can be significantly faster than using message objects, and
custom message data can be read directly without loading message definitions
using [ ` rosgenmsg ` ](rosgenmsg.html) .


[ ![MathWorks](/images/responsive/global/pic-header-mathworks-logo.svg)
](https://www.mathworks.com?s_tid=gn_logo)


Wiki: rosbag/Commandline (last edited 2021-08-25 19:45:58 by  [ Gabriel
Staples ](/Gabriel%20Staples "Gabriel Staples @
75-18-248-60.lightspeed.snrmca.sbcglobal.net\[75.18.248.60\]") )


  * [ check ](/rosbag/Commandline#check)
    * Determine whether a bag is playable in the current system, or if it can be migrated.


[ AttributeError's when running Python scripts
](/question/363102/attributeerrors-when-running-python-scripts/)


[ ![tryan gravatar
image](//www.gravatar.com/avatar/4cd1a4a3c51b6947acbcfb58c7f1f988?s=32&d=identicon&r=PG)
](/users/33908/tryan/)


    * Evaluate and print a Python expression for verbose debugging. Uses same variables as filter expression.

                $ rosbag filter --print="'%s @ %d.%d: %s' % (topic, t.secs, t.nsecs, m.data)" big.bag small.bag "topic == '/chatter'"


    pub = rospublisher("/scan","sensor_msgs/LaserScan","DataFormat","struct")
    msg = rosmessage(pub)


    NO MATCH hello world 68
    NO MATCH hello world 69
    NO MATCH hello world 70
    MATCH hello world 71
    NO MATCH hello world 72
    NO MATCH hello world 73


` -n ` , ` --noplugins `


[ example ](readmessages.html#buqn1u_-1)


sudo apt update && sudo apt install ripgrep


For more information, see [ Improve Performance of ROS Using Message
Structures ](../ug/improve-performance-of-ros-using-message-structures.html) .


  * ` -p PREFIX ` , ` --prefix=PREFIX `
    * prefix all output topics


Last updated: **Mar 17 '21**


    * Do not load rule files via plugins.

                $ rosbag check -n diag.bag


* Use the TCP_NODELAY transport hint when subscribing to topics


* [ Robotics and Autonomous Systems  ](../../overview/robotics-and-autonomous-systems.html?s_tid=hc_product_group_bc)


` -y ` , ` --yaml `


Select a subset of the messages based on their timestamp and topic.


[ ![](/custom/images/brought_by_horiz.png) ](https://www.openrobotics.org/)


    msgs = readMessages(bagMsgs2)

    msgs= _99×1 cell array_
        {1x1 Odometry}
        {1x1 Odometry}
        {1x1 Odometry}
        {1x1 Odometry}
        {1x1 Odometry}
        {1x1 Odometry}
        {1x1 Odometry}
        {1x1 Odometry}
        {1x1 Odometry}
        {1x1 Odometry}
        {1x1 Odometry}
        {1x1 Odometry}
        {1x1 Odometry}
        {1x1 Odometry}
        {1x1 Odometry}
        {1x1 Odometry}
          ⋮


` -h ` , ` --help `


` -tcpnodelay `


##  rosbag play


[ Dataset that has camera,radar and imu ](/question/394720/dataset-that-has-
cameraradar-and-imu/)


##  Private Attributes

---
[ Bag ](classrosbag_1_1Bag.html) const *  |  [ bag_
](classrosbag_1_1MessageInstance.html#a48e1546589dadba572a63ca4aac4ee4f)
[ ConnectionInfo ](structrosbag_1_1ConnectionInfo.html) const *  |  [
connection_info_
](classrosbag_1_1MessageInstance.html#aea72c357275bd9b7c07595d0f1934719)
const [ IndexEntry ](structrosbag_1_1IndexEntry.html) |  [ index_entry_
](classrosbag_1_1MessageInstance.html#af42e039eff56cad39e1078420abb46f0)

##  Friends

---
class  |  [ View
](classrosbag_1_1MessageInstance.html#a018ff8a950133459fda57a235706a80b)

##  Detailed Description
A class pointing into a bag file.
The [ MessageInstance ](classrosbag_1_1MessageInstance.html "A class pointing
into a bag file.") class itself is fairly light weight. It simply contains a
pointer to a bag-file and the index_entry necessary to get access to the
corresponding data.
It adheres to the necessary [ ros::message_traits
](namespaceros_1_1message__traits.html) to be directly serializable.
Definition at line [ 91 ](message__instance_8h_source.html#l00091) of file [
message_instance.h ](message__instance_8h_source.html) .
##  Constructor & Destructor Documentation


In a future release,  ROS Toolbox  will use message structures instead of
objects for ROS messages.


  * [ reindex ](/rosbag/Commandline#reindex)
    * Reindex one or more broken bag files.


[ Asdewar ](/users/71807/asdewar/)
11  ●  2  ●  2  ●  3


` msgs = readMessages(bag,rows)  `


[ ![ROS Answers logo](/m/ros/media/images/logoros.png?v=28) ](/questions/)


Contents


**Introduced in R2019b**


[ collapse all in page ](javascript:void\(0\);)


[ ![ros.org](/custom/images/ros_org.png) ](/) |  [ About
](http://www.ros.org/about-ros) | [ Support ](/Support) | [ Discussion Forum
](http://discourse.ros.org/) | [ Index ](http://index.ros.org/) | [ Service
Status ](http://status.ros.org/) | [ ros @ Robotics Stack Exchange
](https://robotics.stackexchange.com/questions/tagged/ros)
---|---
![](/custom/images/menu_left.png) [
![Documentation](/custom/images/menu_documentation.png) ](/)
![](/custom/images/menu_spacer.png) [ ![Browse
Software](/custom/images/menu_browse_software.png)
](https://index.ros.org/packages) ![](/custom/images/menu_spacer.png) [
![News](/custom/images/menu_news.png) ](https://discourse.ros.org/c/general)
![](/custom/images/menu_spacer.png) [
![Download](/custom/images/menu_download.png) ](/ROS/Installation)
![](/custom/images/menu_right.png)

  * [ rosbag ](/rosbag)
  * [ Tutorials ](/rosbag/Tutorials)
  * [ reading msgs from a bag file ](/rosbag/Tutorials/reading%20msgs%20from%20a%20bag%20file)


##  Comments


* [ std_msgs ](/questions/scope:all/sort:activity-desc/tags:std_msgs/page:1/)


  * [ record ](/rosbag/Commandline#record)
    * Record a bag file with the contents of specified topics.


1. [ ROS/Tutorials/reading msgs from a bag file ](/ROS/Tutorials/reading%20msgs%20from%20a%20bag%20file) \- learn how to use the ` ros_readbagfile ` command-line tool. General format:  ` ros_readbagfile <mybagfile.bag> [topic1] [topic2] [topic3] [...] [topic1000] `


The [ rosbag ](/rosbag) command-line tool provides functionality for ROS [
bags ](/Bags) .


Asked: ** 2021-03-16 15:14:04 -0500  **


Note: if your terminal still says it cannot find the command when trying to
run it, you may need to ensure ` ~/bin ` is part of your ` PATH ` variable.
See [ my answer here for details
](https://answers.ros.org/question/371583/ros_readbagfile-command-not-
found/?answer=403354#post-id-403354) .


` -j ` , ` --bz2 `


Choose a web site to get translated content where available and see local
events and offers. Based on your location, we recommend that you select: ****
.


* Advanced. Record to chunks of SIZE KB (Default: 768). This is a buffer within the bag file object. Lowering this value will result in more writes to disk.


You'll see:


[ **updated 2021-03-17 08:55:59 -0500  ** ](/answers/374173/revisions/)


_Example output:_


[ example ](readmessages.html#mw_b0d9f932-8f6a-4485-9695-b25bf8075b73)


##  rosbag compress


        # (preferred, so you can easily see it is still running): write to the
    # topics.yaml file AND print to stdout
    time ros_readbagfile demo.bag /obs1/gps/fix /diagnostics_agg | tee topics.yaml


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Select a Web Site


* Use an internal buffer of SIZE MB (Default: 256, 0 = infinite). This is the message queue of the recorder object, before messages are being passed on to the bag. Lowering this value might result in messages being dropped before they reach the recording process.


` -h ` , ` --help `


` ` msgs ` = readMessages(  ___  ,"DataFormat",Format) ` returns data as a
cell array of structures or cell array of message objects using either set of
the previous input arguments. Specify ` Format ` as either ` "struct" ` or `
"object" ` .


|  [ Ask Your Question ](/questions/ask/)
---|---|---|---

0


##  ◆  MessageInstance()
|  rosbag::MessageInstance::MessageInstance  |  (  |  [ ConnectionInfo
](structrosbag_1_1ConnectionInfo.html) const *  |  _connection_info_ ,
---|---|---|---
|  |  [ IndexEntry ](structrosbag_1_1IndexEntry.html) const & |  _index_ ,
|  |  [ Bag ](classrosbag_1_1Bag.html) const & |  _bag_
|  )  |  |
private

Definition at line [ 38 ](message__instance_8cpp_source.html#l00038) of file [
message_instance.cpp ](message__instance_8cpp_source.html) .
##  Member Function Documentation
##  ◆  getCallerId()
string rosbag::MessageInstance::getCallerId  |  (  |  |  )  |  const
---|---|---|---|---

Definition at line [ 51 ](message__instance_8cpp_source.html#l00051) of file [
message_instance.cpp ](message__instance_8cpp_source.html) .
##  ◆  getConnectionHeader()
[ shared_ptr
](../../../../api/roscpp_traits/html/classboost_1_1shared__ptr.html) < [
ros::M_string
](../../../../api/cpp_common/html/namespaceros.html#a3d75f50002c0066a51761a9bc5102f2b)
> rosbag::MessageInstance::getConnectionHeader  |  (  |  |  )  |  const
---|---|---|---|---

Definition at line [ 49 ](message__instance_8cpp_source.html#l00049) of file [
message_instance.cpp ](message__instance_8cpp_source.html) .
##  ◆  getDataType()
string const & rosbag::MessageInstance::getDataType  |  (  |  |  )  |  const
---|---|---|---|---

Definition at line [ 45 ](message__instance_8cpp_source.html#l00045) of file [
message_instance.cpp ](message__instance_8cpp_source.html) .
##  ◆  getMD5Sum()
string const & rosbag::MessageInstance::getMD5Sum  |  (  |  |  )  |  const
---|---|---|---|---

Definition at line [ 46 ](message__instance_8cpp_source.html#l00046) of file [
message_instance.cpp ](message__instance_8cpp_source.html) .
##  ◆  getMessageDefinition()
string const & rosbag::MessageInstance::getMessageDefinition  |  (  |  |  )  |
const
---|---|---|---|---

Definition at line [ 47 ](message__instance_8cpp_source.html#l00047) of file [
message_instance.cpp ](message__instance_8cpp_source.html) .
##  ◆  getTime()
[ Time ](../../../../api/rostime/html/classros_1_1Time.html) const &
rosbag::MessageInstance::getTime  |  (  |  |  )  |  const
---|---|---|---|---


##  Output Arguments


` ` msgs ` = readMessages(  ` bag ` ) ` returns data from all the messages in
the ` BagSelection ` or ` rosbagreader ` object ` bag ` . The messages are
returned in a cell array of messages. To get a ` BagSelection ` object, use [
` rosbag ` ](rosbag.html) .


` msgs = readMessages(bag)  `


[ ![MathWorks](/images/responsive/global/pic-header-mathworks-logo.svg)
](https://www.mathworks.com?s_tid=gn_logo)


` --chunksize=SIZE `


[ ![tryan gravatar
image](//www.gravatar.com/avatar/4cd1a4a3c51b6947acbcfb58c7f1f988?s=16&d=identicon&r=PG)
](/users/33908/tryan/) [ tryan ](/users/33908/tryan/) (  2021-03-29 09:47:32
-0500  )  edit


  1. See Also:
  2. rosbag command-line tool:
    1. rosbag record
    2. rosbag info
    3. rosbag play
    4. rosbag check
    5. rosbag fix
    6. rosbag filter
    7. rosbag compress
    8. rosbag decompress
    9. rosbag reindex


##  More .yaml file analysis


##  Question Tools


    * Print information in [ YAML ](http://www.yaml.org) format.

                $ rosbag info -y /path/to/my.bag


    $ time rg 'key: "piksi_' topics.yaml | sort -V | awk '!seen[$0]++'
            key: "piksi_llh_diag: Frequency Status"
            key: "piksi_rtk_diag: Frequency Status"
            key: "piksi_rtk_diag: Piksi Status"
            key: "piksi_time_diag: Frequency Status"

    real    0m0.009s
    user    0m0.003s
    sys     0m0.011s


Definition at line [ 43 ](message__instance_8cpp_source.html#l00043) of file [
message_instance.cpp ](message__instance_8cpp_source.html) .
##  ◆  getTopic()
string const & rosbag::MessageInstance::getTopic  |  (  |  |  )  |  const
---|---|---|---|---

Definition at line [ 44 ](message__instance_8cpp_source.html#l00044) of file [
message_instance.cpp ](message__instance_8cpp_source.html) .
##  ◆  instantiate()
template<class T >
[ boost::shared_ptr
](../../../../api/roscpp_traits/html/classboost_1_1shared__ptr.html) < T >
rosbag::MessageInstance::instantiate
---

Templated call to instantiate a message.
returns NULL pointer if incompatible
Definition at line [ 161 ](message__instance_8h_source.html#l00161) of file [
message_instance.h ](message__instance_8h_source.html) .
##  ◆  isLatching()
bool rosbag::MessageInstance::isLatching  |  (  |  |  )  |  const
---|---|---|---|---

Definition at line [ 56 ](message__instance_8cpp_source.html#l00056) of file [
message_instance.cpp ](message__instance_8cpp_source.html) .
##  ◆  isType()
template<class T >
bool rosbag::MessageInstance::isType
---

Test whether the underlying message of the specified type.
returns true iff the message is of the template type
Definition at line [ 155 ](message__instance_8h_source.html#l00155) of file [
message_instance.h ](message__instance_8h_source.html) .
##  ◆  size()
uint32_t rosbag::MessageInstance::size  |  (  |  |  )  |  const
---|---|---|---|---

Size of serialized message.
Definition at line [ 61 ](message__instance_8cpp_source.html#l00061) of file [
    message_instance.cpp ](message__instance_8cpp_source.html) .
##  ◆  write()
template<typename Stream >
void rosbag::MessageInstance::write  |  (  |  [ Stream
](classrosbag_1_1Stream.html) & |  _stream_ |  )  |  const
---|---|---|---|---|---

Write serialized message contents out to a stream.
Definition at line [ 169 ](message__instance_8h_source.html#l00169) of file [
message_instance.h ](message__instance_8h_source.html) .


  * [ filter ](/rosbag/Commandline#filter)
    * Convert a bag file using Python expressions.


Hi everyone,using the Python API I would like to write a message in a rosbag
file.


Close


Definition at line [ 132 ](message__instance_8h_source.html#l00132) of file [
message_instance.h ](message__instance_8h_source.html) .
* * *
The documentation for this class was generated from the following files:
  * [ message_instance.h ](message__instance_8h_source.html)
  * [ message_instance.cpp ](message__instance_8cpp_source.html)

* * *
[ rosbag_storage ](http://wiki.ros.org/rosbag_storage)
Author(s): Dirk Thomas  , Jacob Perron  autogenerated on Thu Nov 23 2023
04:01:58


  2. Because ` rostopic ` can only read **1 single topic at a time** , whereas ` ros_readbagfile ` can read **any number of topics at once!**

        ros_readbagfile <mybagfile.bag> [topic1] [topic2] [topic3] [...] [topic1000]


    * Only record NUM messages on each topic.

                $ rosbag record -l 1000 /chatter


#  Option 1: play back the messages immediately and look at the output in
multiple terminals


    * Write to directory DIR.

                $ rosbag decompress --output-dir=uncompressed *.bag


    real    0m1.003s
    user    0m0.620s
    sys 0m0.283s


` -h ` , ` --help `


First time here? Check out the FAQ!


rosbag filter input.bag output.bag "t.to_sec() <= 1284703931.86"


  * ` decompress <bag-files> `
    * Decompress the given bag files.

                $ rosbag decompress *.bag


© 1994-2024 The MathWorks, Inc.


Index of the messages in the rosbag, specified as a [ ` BagSelection `
](bagselection.html) or [ ` rosbagreader ` ](rosbagreader.html) object.


    * Specify the maximum duration of the recorded bag file.

                $ rosbag record --duration=30 /chatter
        $ rosbag record --duration=5m /chatter
        $ rosbag record --duration=2h /chatter


Wiki: rosbag/Tutorials/reading msgs from a bag file (last edited 2024-04-16
15:57:36 by  [ KatherineScott ](/KatherineScott "KatherineScott @
157.131.162.29\[157.131.162.29\]") )


So in our case, the command would be:


  * ` info <bag-files> `
    * Display a summary of the contents of the bag files.

                $ rosbag info session*.bag


###  Example 1:


[ What are rosbag --split and --chunksize useful for? ](/question/363852/what-
are-rosbag-split-and-chunksize-useful-for/)


Read messages as a structure. Specify the ` DataFormat ` name-value pair when
reading the messages. Inspect the first structure in the returned cell array
of structures.


    * Do not load rule files via plugins.

                $ rosbag fix -n old.bag repaired.bag


    bagselect = rosbag('ex_multiple_topics.bag');
    bagselect2 = select(bagselect,'Time',...
    [bagselect.StartTime bagselect.StartTime + 1],'Topic','/odom');


[ ![cc-by-sa](/m/default/media/images/cc-by-sa.png?v=28)
](http://creativecommons.org/licenses/by-sa/3.0/legalcode) ROS Answers is
licensed under Creative Commons Attribution 3.0 Content on this site is
licensed under a [ Creative Commons Attribution Share Alike 3.0
](http://creativecommons.org/licenses/by-sa/3.0/legalcode) license.


###  Europe


` --max-splits=MAX_SPLITS ` New in ROS Kinetic


  * [ América Latina ](https://la.mathworks.com) (Español)
  * [ Canada ](https://www.mathworks.com) (English)
  * [ United States ](https://www.mathworks.com) (English)


` -h ` , ` --help `


    * Force overwriting of backup file it it exists.

                $ rosbag compress -f *.bag


If you do not want to observe playback timing, the ` -i ` option will playback
all messages from the file as fast as possible. Note that for large files this
will often lead to exceeding your incoming buffers.


    bagMsgs2 = select(bagMsgs,...
        Time=[bagMsgs.StartTime bagMsgs.StartTime + 1],...
        Topic='/odom')

    bagMsgs2 =
      rosbagreader with properties:

               FilePath: '/tmp/Bdoc24a_2528353_1173766/tp199fe096/ros-ex26633229/ex_multiple_topics.bag'
              StartTime: 201.3400
                EndTime: 202.3200
            NumMessages: 99
        AvailableTopics: [1x3 table]
        AvailableFrames: {0x1 cell}
            MessageList: [99x4 table]


` -b SIZE ` , ` --buffsize=SIZE `


##  rosbag record


##  Related questions


    * Match topics using regular expressions.

                $ rosbag record -e "/(.*)_stereo/(left|right)/image_rect_color"


* United States


    * Write to directory DIR.

                $ rosbag compress --output-dir=compressed *.bag


    msg = rosmessage("/scan","sensor_msgs/LaserScan","DataFormat","struct")
    ...
    pub = rospublisher("/scan","sensor_msgs/LaserScan","DataFormat","struct")


    rosbag record --duration=30 --output-name=/tmp/mybagfile.bag \
        /topic1 /topic2 /topic3


    $ time rg '(key: "GPS|key: "Duration|key: "Minimum)' topics.yaml | sort -V | awk '!seen[$0]++'
            key: "Duration of window (s)"
            key: "GPS RTK height difference (m)"
            key: "GPS RTK horizontal accuracy (m)"
            key: "GPS RTK meters east"
            key: "GPS RTK meters north"
            key: "GPS RTK orientation east"
            key: "GPS RTK orientation north"
            key: "GPS RTK orientation up"
            key: "GPS RTK solution status (4 = good)"
            key: "GPS RTK velocity east"
            key: "GPS RTK velocity flags"
            key: "GPS RTK velocity north"
            key: "GPS RTK velocity up"
            key: "GPS altitude"
            key: "GPS latitude"
            key: "GPS lat/lon horizontal accuracy (m)"
            key: "GPS lat/lon solution status"
            key: "GPS longitude"
            key: "Minimum acceptable frequency (Hz)"

    real    0m0.023s
    user    0m0.023s
    sys     0m0.008s


    bagMsgs = rosbagreader("ex_multiple_topics.bag")

    bagMsgs =
      rosbagreader with properties:

               FilePath: '/tmp/Bdoc24a_2528353_1173766/tp199fe096/ros-ex26633229/ex_multiple_topics.bag'
              StartTime: 201.3400
                EndTime: 321.3400
            NumMessages: 36963
        AvailableTopics: [4x3 table]
        AvailableFrames: {0x1 cell}
            MessageList: [36963x4 table]


` rosbag reindex ` is a command-line tool for repairing broken bag files (or
bag files recorded prior to ROS version 0.11.) If a bag was not closed cleanly
for any reason, then the index information may be corrupted. Use this tool to
reread the message data and rebuild the index.


The ` ros_readbagfile ` script, however, takes only **1 min 37 sec** on the
same computer to read the same topic from the same 18 GB bag file! Therefore,
` ros_readbagfile ` is 11.5/(1+37/60) = **~7x faster!**


` -g RULEFILE ` , ` --genrules=RULEFILE `


First, you need a bag file. Produce your own by following this tutorial ( [
ROS/Tutorials/Recording and playing back data
](/ROS/Tutorials/Recording%20and%20playing%20back%20data) ).


  *[
              2021-03-16 15:14:04 -0500
             ]: 2021-03-16 15:14:04 -0500
  *[
             2021-03-16 20:04:01 -0500
            ]: 2021-03-16 20:04:01 -0500
  *[
             2021-03-17 07:11:23 -0500
            ]: 2021-03-17 07:11:23 -0500
  *[
              2021-03-17 08:54:13 -0500
             ]: 2021-03-17 08:54:13 -0500
  *[
              2021-03-17 08:55:59 -0500
             ]: 2021-03-17 08:55:59 -0500
  *[
             2021-03-25 09:31:28 -0500
            ]: 2021-03-25 09:31:28 -0500
  *[
             2021-03-25 09:56:19 -0500
            ]: 2021-03-25 09:56:19 -0500
  *[
             2021-03-25 10:48:23 -0500
            ]: 2021-03-25 10:48:23 -0500
  *[
             2021-03-29 09:47:32 -0500
            ]: 2021-03-29 09:47:32 -0500
  *[
        2021-03-16 15:14:04 -0500
       ]: 2021-03-16 15:14:04 -0500
  *[
        2024-04-18 18:36:16 -0500
       ]: 2024-04-18 18:36:16 -0500


With the library std_msgs I can write standar types like str or unint, but i
don't know how to do it with a custom message.


##  Examples


    * Suppress noncritical messages.

                $ rosbag decompress -q *.bag


You may have valid reasons, but it's still unclear to me why a bag is involved
if you don't expect to use ROS. To avoid ROS dependencies, you could
(de)serialize the data yourself or using some other tool to work with a non-
bag format. If you want to use a bag without ROS, you can still do so by
(de)serializeng according to the [ bag format
](http://wiki.ros.org/Bags/Format/2.0) , though.


        $ time rosbag info demo.bag
    path:        demo.bag
    version:     2.0
    duration:    20.0s
    start:       Mar 21 2017 19:37:58.00 (1490150278.00)
    end:         Mar 21 2017 19:38:17.00 (1490150298.00)
    size:        696.2 MB
    messages:    5390
    compression: none [600/600 chunks]
    types:       bond/Status                      [eacc84bf5d65b6777d4c50f463dfb9c8]
                 diagnostic_msgs/DiagnosticArray  [60810da900de1dd6ddd437c3503511da]
                 diagnostic_msgs/DiagnosticStatus [d0ce08bc6e5ba34c7754f563a9cabaf1]
                 nav_msgs/Odometry                [cd5e73d190d741a2f92e81eda573aca7]
                 radar_driver/RadarTracks         [6a2de2f790cb8bb0e149d45d297462f8]
                 sensor_msgs/Image                [060021388200f6f0f447d0fcd9c64743]
                 sensor_msgs/NavSatFix            [2d3a8cd499b9b4a0249fb98fd05cfa48]
                 sensor_msgs/PointCloud2          [1158d486dd51d683ce2f1be655c3c181]
                 sensor_msgs/Range                [c005c34273dc426c67a020a87bc24148]
                 sensor_msgs/TimeReference        [fded64a0265108ba86c3d38fb11c0c16]
                 tf2_msgs/TFMessage               [94810edda583a504dfda3829e70d7eec]
                 velodyne_msgs/VelodyneScan       [50804fc9533a0e579e6322c04ae70566]
    topics:      /diagnostics                      140 msgs    : diagnostic_msgs/DiagnosticArray
                 /diagnostics_agg                   40 msgs    : diagnostic_msgs/DiagnosticArray
                 /diagnostics_toplevel_state        40 msgs    : diagnostic_msgs/DiagnosticStatus
                 /gps/fix                          146 msgs    : sensor_msgs/NavSatFix
                 /gps/rtkfix                       200 msgs    : nav_msgs/Odometry
                 /gps/time                         192 msgs    : sensor_msgs/TimeReference
                 /image_raw                        600 msgs    : sensor_msgs/Image
                 /obs1/gps/fix                      30 msgs    : sensor_msgs/NavSatFix
                 /obs1/gps/rtkfix                  200 msgs    : nav_msgs/Odometry
                 /obs1/gps/time                    136 msgs    : sensor_msgs/TimeReference
                 /radar/points                     400 msgs    : sensor_msgs/PointCloud2
                 /radar/range                      400 msgs    : sensor_msgs/Range
                 /radar/tracks                     400 msgs    : radar_driver/RadarTracks
                 /tf                              1986 msgs    : tf2_msgs/TFMessage
                 /velodyne_nodelet_manager/bond     80 msgs    : bond/Status
                 /velodyne_packets                 200 msgs    : velodyne_msgs/VelodyneScan
                 /velodyne_points                  200 msgs    : sensor_msgs/PointCloud2


  * Immutable Page
  * Comments
  * [ Info ](/action/info/rosbag/Commandline?action=info)
  * [ Attachments ](/action/AttachFile/rosbag/Commandline?action=AttachFile)
  * More Actions:  Raw Text  Print View  Render as Docbook  Delete Cache  \------------------------  Check Spelling  Like Pages  Local Site Map  \------------------------  Rename Page  Copy Page  Delete Page  \------------------------  My Pages  Subscribe User  \------------------------  Remove Spam  Revert to this revision  Package Pages  Sync Pages  \------------------------  CreatePdfDocument  Load  RawFile  Save  SlideShow


  * ` --lz4 `
    * Use LZ4 to compress data.

                $ rosbag compress --lz4 *.bag


Skip to content


    * Publish a message when the record begin to write a new bag (topic = " ` begin_write ` ").

                $ rosbag record -p


##  Version History


**Description:** Learn two ways to read messages from desired topics in a bag
file, including using the really handy **ros_readbagfile** script.

**Keywords:** data, rosbag, extract, play, info, bag, messages, readbagfile,
ros_readbagfile

**Tutorial Level:** BEGINNER

**Next Tutorial:** [ Producing filtered bag files
](/rosbag/Tutorials/Producing%20filtered%20bag%20files)


I didn't actually test this code, so let me know if you run into problems.


See more instructions and usage examples on the [ rosbag migration page
](/rosbag/migration#converting) .


###  ` msgs ` — ROS message data
object | cell array of message objects | cell array of structures


  * ` -l ` , ` --loop `
    * Loop playback.

                $ rosbag play -l recorded1.bag


The rest of this tutorial will be done assuming you've downloaded the
webviz.io demo bag file using the ` wget ` command as shown above. You will go
through two options to read/extract messages from the bag file.


Close Mobile Search


    * Force overwriting of backup file it it exists.

                $ rosbag reindex -f *.bag


  1. Download or record a bag file
  2. Option 1: play back the messages immediately and look at the output in multiple terminals
  3. Option 2: use the ros_readbagfile script to easily extract the topics of interest
    1. More .yaml file analysis
      1. Example 1:
      2. Example 2:
  4. Why use `ros_readbagfile` for this purpose instead of `rostopic echo -b`?


` -q ` , ` --quiet `


  * [ compress ](/rosbag/Commandline#compress)
    * Compress one or more bag files.


  * ` -u SEC ` , ` --duration=SEC `
    * Play only SEC seconds from the bag files.

                $ rosbag play -u 240 recorded1.bag


  5. Repeat this process for as many topics as you like. Each topic must have its own terminal.
  6. Open up another terminal to play the bag file. We will now play back the bag file as quickly as possible (using the ` --immediate ` option), publishing ONLY the topics of interest. The format is:

        time rosbag play --immediate demo.bag --topics /topic1 /topic2 /topic3 /topicN


If you are recording messages at a high bandwidth, such as from cameras, it is
strongly recommended you run ` rosbag record ` on the same machine as the
camera, and specify the file destination as being on the local machine disk.


time rosbag play --immediate demo.bag --topics /obs1/gps/fix /diagnostics_agg


[ Controlling a quadcopter in Gazebo ](/question/327096/controlling-a-
quadcopter-in-gazebo/)


[ subscribe to rss feed ](/feeds/question/374115/ "subscribe to the rss feed")


  * ` -r FACTOR ` , ` --rate=FACTOR `
    * Multiply the publish rate by FACTOR.

                $ rosbag play -r 10 recorded1.bag


Assuming you are on a system with ROS already running, here is a quick command
to record a 30 second snippet of data into a bag file for just topics you are
interested in, ex: ` /topic1 ` , ` /topic2 ` , and ` /topic3 ` . Since we are
setting a duration of 30 seconds, the recording will automatically stop after
this time:


Hi again, I understand what you mean but, I want to do it without installing
ROS in mi computer. There is another way to write a custom message without
using ROS? I want to make a program that can write some messages but without
the user having to worry about installing ROS But thanks a lot, I will
continue searching but if I do not find a solution, I'll use yours


×  ![MathWorks](/images/responsive/global/pic-header-mathworks-logo2.svg)


Retrieve the messages in the selection as a cell array.


_Example usage:_


To use message structures now, set the ` "DataFormat" ` name-value argument to
` "struct" ` . For more information, see [ ROS Message Structures
](readmessages.html#buqn04a_sep_mw_f541fa33-9d06-425c-9f2e-0085cfca490a) .


  * [ Distributions ](/Distributions)
  * [ ROS/Installation ](/ROS/Installation)
  * [ ROS/Tutorials ](/ROS/Tutorials)
  * [ RecentChanges ](/RecentChanges)
  * [ rosbag/Commandline ](/rosbag/Commandline)


  7. Done! Now go look at your two terminals which were each subsribed to a topic, and you'll see the output of all messages for each topic type, in YAML format, with a ` --- ` line between each message. Use a text editor of your choice, preferably with Syntax Highlighting for YAML file types (ex: Sublime Text 3) to view the messages in the files. The last two messages in **topic1.yaml** , for instance, look like this:

        ---
    header:
      seq: 4027
      stamp:
        secs: 1490150296
        nsecs:  66947432
      frame_id: "gps"
    status:
      status: 0
      service: 1
    latitude: 37.4008017844
    longitude: -122.108119889
    altitude: -6.4380177824
    position_covariance: [1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0]
    position_covariance_type: 0
    ---
    header:
      seq: 4028
      stamp:
        secs: 1490150297
        nsecs: 744347249
      frame_id: "gps"
    status:
      status: 0
      service: 1
    latitude: 37.4007565466
    longitude: -122.108159482
    altitude: -6.35130467023
    position_covariance: [1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0]
    position_covariance_type: 0
    ---


add a comment


  * ` -s SEC ` , ` --start=SEC `
    * Start SEC seconds into the bags.

                $ rosbag play -s 5 recorded1.bag


These are described in greater detail in the following sections.


[ about ](/about/) |  [ faq ](/faq/) |  [ help ](/help/ "help") |  [ privacy
policy ](/privacy/) |  [ terms of service ](/terms/)


  * ` record <topic-names> `
    * Record a bag file with the contents of the specified topics.

                $ rosbag record rosout tf cmd_vel


  * ` --pause-topics `
    * topics to pause on during playback


[ Open Live Script
](matlab:openExample\('ros/CreateRosbagSelectionUsingRosbagreaderObjectExample'\))


Now view **topics.yaml** with your preferred text editor or viewer (ex:
Sublime Text 4, gedit, emacs, vim, ` less ` , etc) to see all of the messages
it extracted from the bag file.


  * ` --bags=BAGS `
    * bags files to play back from


    * Record all topics.

                $ rosbag record -a


    * Exclude topics matching the given regular expression (subtracts from ` -a ` or ` -e ` ).

                $ rosbag record -e "/wide_stereo(.*)" -x "(.*)/points(.*)"


**Note**


###  Return ROS Messages as a Cell Array


  * ` --rate-control-max-delay=RATE_CONTROL_MAX_DELAY `
    * maximum time difference from ` <rate-control-topic> ` before pausing


[ __ ](/questions/) |


time rg '(key: "GPS|key: "Duration|key: "Minimum)' topics.yaml | sort -V | awk '!seen[$0]++'


Help Center


In a future release, ROS messages will use structures by default and ROS
message objects will be removed.


You'll see:


watch -n 1 'du -sk topics.yaml | awk '\''{printf "%.3f MiB %s\n", $1/1024, $2}'\'''


Read rosbag and filter by topic and time.


The message's format is described in this file [ https://github.com/uzh-
rpg/rpg_dvs_ro... ](https://github.com/uzh-
rpg/rpg_dvs_ros/blob/master/dvs_msgs/msg/Event.msg)


Notice that there are 30 messages published on topic ` /obs1/gps/fix ` , and
40 on topic ` /diagnostics_agg ` . Let's just extract those.


Return certain message properties as a time series.


` -q ` , ` --quiet `


    * Suppress noncritical messages.

                $ rosbag compress -q *.bag


  * readMessages
  * On this page
  * Syntax
  * Description
  * Examples
    * Return ROS Messages as a Cell Array
    * Read Messages from a rosbag as a Structure
    * **Create rosbag Selection Using** **` rosbagreader ` ** **Object**
  * Input Arguments
    * bag
    * rows
  * Output Arguments
    * msgs
  * Version History
    * ROS Message Structures
  * See Also


  * ` --skip-empty=SEC `
    * Skip regions in the bag with no messages for more than SEC seconds.

                $ rosbag play --skip-empty=1 recorded1.bag


* [ Login ](/action/login/rosbag/Commandline?action=login)


` -h ` , ` --help `


[ Help Center ](../../index.html) [ Help Center ](../../index.html)


[ ![Asdewar gravatar image](/m/default/media/images/nophoto.png?v=28)
](/users/71807/asdewar/) [ Asdewar ](/users/71807/asdewar/) (  2021-03-25
10:48:23 -0500  )  edit


* [ Login ](/action/login/rosbag/Tutorials/reading%20msgs%20from%20a%20bag%20file?action=login)


` -f ` , ` --force `


  * ` -d SEC ` , ` --delay=SEC `
    * Sleep SEC seconds after every advertise call (to allow subscribers to connect).

                $ rosbag play -d 5 recorded1.bag


...and here is the full output:


  * ` -q ` , ` --quiet `
    * Suppress console output.

                $ rosbag play -q recorded1.bag


If it's a custom message as part of a third-party package, the message
generation should happen automatically when you build/install that package. To
check if it's installed properly and ROS can find it, you can run ` rosmsg
show <package_name>/<msg_name> ` in a terminal. In this case, it would be:


    * Record all topics subscribed to by a specific node

                $ rosbag record --node=/joy_teleop


  1. Because ` rostopic ` is **extremley slow!** This command, running on a fast computer (4-core/8-thread Pentium i7 w/m.2 SSD), for instance, takes **11.5 minutes** to read an 18 GB bag file!

        time rostopic echo -b large_bag_file.bag /topic1


#  Wiki


  * ` -i ` , ` --immediate `
    * Play back all messages without waiting.

                $ rosbag play -i recorded1.bag


##  MATLAB Command


The ` rg 'key: "piksi_' topics.yaml ` part searches the "topics.yaml" text
file for the ` 'key: "piksi_' ` string, the ` sort -V ` part sorts all of the
output lines, and the ` awk '!seen[$0]++' ` part removes duplicate entries, so
that you only see one line of each match.


[ ALL ](/questions/scope:all/sort:activity-desc/page:1/) [ UNANSWERED
](/questions/scope:unanswered/sort:answers-asc/page:1/)


$ rosbag record -e "(.*)sensors(.*)"


##  rosbag info


[ ![tryan gravatar
image](//www.gravatar.com/avatar/4cd1a4a3c51b6947acbcfb58c7f1f988?s=16&d=identicon&r=PG)
](/users/33908/tryan/) [ tryan ](/users/33908/tryan/) (  2021-03-16 20:04:01
-0500  )  edit


[ URDF model using the a variable parameter ](/question/361766/urdf-model-
using-the-a-variable-parameter/)


##  See Also


    xPoints = cellfun(@(m) double(m.X),msgStructs);
    yPoints = cellfun(@(m) double(m.Y),msgStructs);
    plot(xPoints,yPoints)


  * Documentation
  * [ Examples ](../examples.html?category=ros-bag-file-logging-and-analysis&s_tid=CRUX_topnav)
  * [ Functions ](../referencelist.html?type=function&category=ros-bag-file-logging-and-analysis&s_tid=CRUX_topnav)
  * [ Blocks ](../referencelist.html?type=block&category=ros-bag-file-logging-and-analysis&s_tid=CRUX_topnav)
  * [ Apps ](../referencelist.html?type=app&category=ros-bag-file-logging-and-analysis&s_tid=CRUX_topnav)
  * [ Videos ](/support/search.html?fq\[\]=asset_type_name:video%20category:ros/ros-bag-file-logging-and-analysis&s_tid=CRUX_topnav)
  * [ Answers ](/support/search.html?fq\[\]=asset_type_name:answer%20category:ros/ros-bag-file-logging-and-analysis&s_tid=CRUX_topnav)


* [ melodic ](/questions/scope:all/sort:activity-desc/tags:melodic/page:1/)


###  Asia Pacific


    * Write to directory DIR.

                $ rosbag reindex --output-dir=reindexed *.bag


  2. In terminal 1 (this terminal, for example), start up a ros core, which runs the required ROS master node:

        roscore


###  Example 2:


Extract the  _xy_ points from the messages and plot the robot trajectory.


###  Read Messages from a rosbag as a Structure


$ rosbag record -b 1024 /chatter


  * ` -h ` , ` --help `
    * Show the usage and exit.

                $ rosbag play -h


[ ros::Rate::sleep() equivalent in rosserial ](/question/344793/rosratesleep-
equivalent-in-rosserial/)


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ROS message data, returned as an object, cell array of message objects, or
cell array of structures. Data comes from either the ` BagSelection ` object
created using [ ` rosbag ` ](rosbag.html) or the ` rosbagreader ` object.


    ts = timeseries(bagMsgs2,...
        'Pose.Pose.Position.X', ...
        'Twist.Twist.Angular.Y')

      timeseries

      Timeseries contains duplicate times.

      Common Properties:
                Name: '/odom Properties'
                Time: [99x1 double]
            TimeInfo: tsdata.timemetadata
                Data: [99x2 double]
            DataInfo: tsdata.datametadata


  *   * ` -j ` , ` --bz2 `
    * Use BZ2 to compress data.

                $ rosbag compress -j *.bag


Off-Canvas Navigation Menu Toggle


MathWorks


rosmsg show dvs_msgs/Event


Load a rosbag log file and parse out specific messages based on the selected
criteria.


  * ` check <bag-file> `
    * Determine whether or not a bag is playable in the current system.

                $ rosbag check old.bag


Once the headers are available, you can use the message just like any other.
Here's the ` Event ` message added to the [ ` rosbag ` Python API example
](http://wiki.ros.org/rosbag/Code%20API#Python_API) :


bag = rosbag('ros_turtlesim.bag');


Sample output:


[ **answered 2021-03-17 08:54:13 -0500  ** ](/answers/374173/revisions/)


  4. Open up another terminal. Subscribe to the other topic: ` /diagnostics_agg ` .

        rostopic echo /diagnostics_agg | tee topic2.yaml


Let's search for all key data entries which begin with "GPS", "Duration", or
"Minimum". "OR" type regular expression searches take the general format: `
(str1|str2|str3|etc) ` , with ` | ` being read as "or" in this case. So,
searching for "GPS", "Duration", or "Minimum" can be done with the following
regular expression search string: ` '(key: "GPS|key: "Duration|key: "Minimum)'
` .


    uint16 x
    uint16 y
    time ts
    bool polarity


You'll see:


* time of message. The time is represented as a [ rospy ](/rospy) [ Time ](http://pr.willowgarage.com/pr-docs/ros-packages/rospy/html/classrospy_1_1msg_1_1Time.html) object ( ` t.secs ` , ` t.nsecs ` )


[ Open Live Script
](matlab:openExample\('ros/ReadMessagesFromARosbagAsAStructureROSExample'\))


A backup of each bag file (with the extension ` .orig.bag ` ) is made before
the bag is compressed. If the backup file already exists (and the ` -f `
option isn't specified) then the tool will not compress the file.


` ` msgs ` = readMessages(  ` bag ` ,  ` rows ` ) ` returns data from messages
in the rows specified by ` rows ` . The range of the rows is [1, `
bag.NumMessages ` ].


#  Wiki


Resources


  * ` --lz4 `
    * Use LZ4 compression. See [ compress ](/rosbag/Commandline#compress) for details.

                $ rosbag record --lz4 /chatter


` -O NAME ` , ` --output-name=NAME `


##  rosbag reindex


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    * Append to the end of an existing bag migration rule file after loading.

                $ rosbag check -a -g all.bmr diag.bag


_Join the conversation_


Read messages from rosbag


You clicked a link that corresponds to this MATLAB command:


  * [ ![Facebook](/images/responsive/global/ico-facebook.svg) ](https://www.facebook.com/MATLAB)
  * [ ![X](/images/responsive/global/ico-x.svg) ](https://twitter.com/MATLAB)
  * [ ![Instagram](/etc.clientlibs/mathworks/clientlibs/customer-ui/templates/common/resources/images/ico-instagram.svg) ](https://www.instagram.com/matlab/)
  * [ ![YouTube](/images/responsive/global/ico-youtube.svg) ](https://www.youtube.com/user/MATLAB)
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  * [ ![RSS](/images/responsive/global/ico-rss.svg) ](https://www.mathworks.com/company/rss.html)


` -h ` , ` --help `


2. Determine the _exact_ topic names you'd like to read from the bag file, by using ` rosbag info ` , as shown in Step 1 of Option 1 above.


  * [ decompress ](/rosbag/Commandline#decompress)
    * Decompress one or more bag files.


#  Page


Run the command by entering it in the MATLAB Command Window. Web browsers do
not support MATLAB commands.


#  User


[ expand all ](javascript:void\(0\);)


Answer:


Record all topics that contain ` sensors ` in their name:


[ ROS TCP Connector C# Lost Publishers & Freezing ](/question/417733/ros-tcp-
connector-c-lost-publishers-freezing/)


[ ![ gravatar image]() ]() [ ]() (  2024-04-18 18:36:16 -0500  )  edit


[ Source for downloading rosbag files containing pointclouds
](/question/282981/source-for-downloading-rosbag-files-containing-
pointclouds/)


Additionally, during playing, you can pause at any time by pressing space.
When paused, you can step through messages by pressing ` s ` .


If you don't want to use ROS, why not just use the lower-level library for
your device (libcaer, I think) instead of ROS messages and bag files, which
have inherent dependencies on ROS components?


####  ROS 2 Documentation