# About geometry_msgs/Twist

Are there any instructions about the meaning of geometry_msgs/Twist elements? e.g. What's the unit of linear and angular, m/s? degree/min? degree/s?

About geometry_msgs/Twist

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3

Hi, These are just msgs in a structured way so that they can be published or subscribed by a node. They are just values. It depends on the node which actually uses them to manipulate robot. It depends on how you want to use it. For example in teleop_base package the teleop_base_keyboard.cpp takes the msgs from keyboard and uses them as m/sec. If your node takes this msgs as mm/sec then the node execution will be accordingly.

You can know the msg types by the following command.

```
rosmsg show geometry_msgs/Twist
```

whose output is

```
geometry_msgs/Vector3 linear
float64 x
float64 y
float64 z
geometry_msgs/Vector3 angular
float64 x
float64 y
float64 z
```

Hope this helps, Karthik

10

Note that the units are defined in REP103 on "Standard Units of Measure and Coordinate Conventions" here: http://www.ros.org/reps/rep-0103.html

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Asked: ** 2011-11-29 16:44:23 -0500 **

Seen: **7,059 times**

Last updated: **Nov 29 '11**

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