[ros-users] topic vs tf

Jeff Rousseau <jrousseau@aptima.com> jrousseau at aptima.com
Fri Dec 9 18:39:47 UTC 2011

One particular use case where a tf-only solution would break down is when you need to share geometric data between robots over a lossy connection (802.11b/g/a, zigbee, etc.)  In a multi-robot use case it is usually infeasible to have a single master, so instead you run a master locally on each robot and forward only the pertinent topics that other robots need access to for whatever particular problem they're trying to solve--since /tf is high-bandwidth you have to resort to sharing geometric topics.

> -----Original Message-----
> From: ros-users-bounces at code.ros.org [mailto:ros-users-
> bounces at code.ros.org] On Behalf Of Thibault Kruse
> Sent: Friday, December 09, 2011 12:14 PM
> To: User discussions
> Subject: [ros-users] topic vs tf
> Hi,
> I am keen on reading an answer to this answers.ros.org question:
> http://answers.ros.org/question/2803/when-should-i-send-geometric-
> information-over-a
> "When should I send geometric information over a topic as opposed to TF?"
> I would think that TF is the best place to publish frames, meaning coordinate
> systems to be used as a point of reference for other geometric data.
> So this would be ideal for robot joints/links, sensor coordinate systems, and
> perceived joints/links of other agents (humans or robots).
> If possible, all those should rather be published in TF rather than anything
> else, I would believe.
> However I do not yet understand whether there is a downside to using TF, or
> some kind of degradation when plenty of frames are being published.
> The only thing I can think of is that rosbag and rxbag cannot treat individual
> transforms, they can only record / replay the whole tf tree.
> Also I guess that data with a lot of noise is not suitable as a reference frame
> for anything, so there is no point in publishing that in TF.
> Other thoughts?
> cheers,
>    Thibault
> _______________________________________________
> ros-users mailing list
> ros-users at code.ros.org
> https://code.ros.org/mailman/listinfo/ros-users

The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer.

More information about the ros-users mailing list