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Effective Robotics Programming with ROS

You're reading from   Effective Robotics Programming with ROS Find out everything you need to know to build powerful robots with the most up-to-date ROS

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Product type Paperback
Published in Dec 2016
Publisher Packt
ISBN-13 9781786463654
Length 468 pages
Edition 3rd Edition
Tools
Concepts
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Authors (3):
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Luis S√°nchez Luis S√°nchez
Author Profile Icon Luis S√°nchez
Luis S√°nchez
Enrique Fernandez Perdomo Enrique Fernandez Perdomo
Author Profile Icon Enrique Fernandez Perdomo
Enrique Fernandez Perdomo
Anil Mahtani Anil Mahtani
Author Profile Icon Anil Mahtani
Anil Mahtani
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Toc

Table of Contents (12) Chapters Close

Preface 1. Getting Started with ROS FREE CHAPTER 2. ROS Architecture and Concepts 3. Visualization and Debugging Tools 4. 3D Modeling and Simulation 5. The Navigation Stack – Robot Setups 6. The Navigation Stack – Beyond Setups 7. Manipulation with MoveIt! 8. Using Sensors and Actuators with ROS 9. Computer Vision 10. Point Clouds Index

Plotting scalar data


Scalar data can be easily plotted with generic tools already available in ROS. Even non-scalar data can be plotted, but with each scalar field plotted separately. That is why we talk about scalar data, because most non-scalar structures are better represented with ad-hoc visualizers, some of which we will see later; for instance, images, poses, orientation/attitude, and so on.

Creating a time series plot with rqt_plot

Scalar data can be plotted as a time series over the time provided by the timestamps of the messages. Then, in the y axis, we can plot our scalar data. The tool for doing so is rqt_plot. It has a powerful argument syntax, which allows you to specify several fields of a structured message in a concise manner; we can also add or remove topics or fields manually from the GUI.

To show rqt_plot in action, we are going to use the example4 node, as it publishes a scalar and a vector (non-scalar) in two different topics, which are temp and accel, respectively. The...

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