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Usage

First time running

$ sudo apt-get install ros-$ROS_DISTRO-rqt
$ sudo apt-get install ros-$ROS_DISTRO-rqt-common-plugins

OR

$ rosdep install rqt_plot

Also if you're on Ubuntu and like to know the most recommended plotting result, simply get a .deb file of pyqtgraph here, which is not available via rosdep. And run it by something like:

$ dpkg -i %NAME_OF_DOT_DEB_FILE%.deb

How to run in general

$ rqt_plot

To specify topic(s) to plot, you need full path name of the topics published. You can find them easily for instance by the command below:

$ rostopic list
/rosout         #  these are only example topics.
/rosout_agg
/turtle1/cmd_vel
/turtle1/color_sensor
/turtle1/pose

To give topic names to plot

There are two ways to give the topic names to rqt_plot as explained in following sections. In both ways, topics that are set in previous run is resumed (as far as the program was shut down without error).

Run from commandline

Both of the following lines plot the same topics.

$ rqt_plot /turtle1/pose/x:y:z
$ rqt_plot /turtle1/pose/x /turtle1/pose/y /turtle1/pose/z

Obviously, if you want to change the topics to plot, you need to restart the program and give the new topic names.

From GUI

Type in the "Topic" input field the full path of the topic name, and press "+" button.

"Topic" field auto-completes the topic name (although it's not fully working as noticed).

Note for the input value syntax

The input value should be the full path to the value, not only the topic name. E.g., in above case the topic /turtle1/pose/x is a member "x" in a published topic "/turtle1/pose", which is defined as "turtlesim/Pose" message.

New short example to show this; say you want to plot a topic called position x of /your_robot/pose topic, which is a type of geometry_msgs/Pose message. This can be plotted by /your_robot/pose/position/x. Possiblly you can figure out this plot name by following steps like this:

• geometry_msgs/Pose contains a member position. Look into its definition by clicking the link at geometry_msgs/Point in the api page.

• You see x as a member of geometry_msgs/Point.

To choose plotting backend type

Currently rqt_plot has three plotting backend options (numbered in recommended order) which can be configured using the setting dialog available via the gear icon in the window title bar:

1. pyqtgraph (fast and needs pyqtgraph to be manually installed which is not in the Ubuntu binary repository as of Sep 2013)

2. matplotlib (slow but always available)

3. qwt plot (fast, but not using message timestamps and needs python-qwt bindings)

By default, backend option is chosen in the order above; the first one found on your system gets used (eg. if your system has matplotlib but not pyqtgraph, your rqt_plot runs with the matplotlib).

User can also select one of them from GUI; click "gear" icon next to question symbol and a dialog should pop up.

Zoom out on time axis

See this post.

Trouble shooting

Topic is not plotted

Check the following:

• Your topic is an array (eg. sensor_msgs/JointState/position)

  • specify an array index (see this thread)

• You didn't give the full path of your topic
• Topic is not being published

  • Use rqt_topic to see the topics being published.

• You are plotting data from a bag file?

  • Use simulation time.

Limitation

Data type

TODO need to figure out which data types are supported

No trajectory supported

See this discussion.

Spline curve is not supported either.