Hi Tully,

> Can you provide a little more insight into what processes you're running,
> how your workflow goes when repeatedly playing a bag file, and how you're
> detecting the jumpy results?
>
> I'm not sure which process in which you are seeing the jumpy results in, but
> if you just restart that node it will clear the tf data for that node.  tf
> is an entirely distributed system.  All data is stored locally in each
> node.
Ah, that makes it a lot clearer! I was assuming that there was some 
central TF buffer in the core. That also means that calling the 
"clear()" Josh mentioned won't have any effect, since the TF buffer of a 
newly started node is cleared anyway.

With that information, I think my problem was a mixture between an 
already running roscore, rviz and another node. Because those remained 
running when I restarted the playback of the bag file, new data arrived 
which was slightly in the past, at times that were already observed.

I suppose I'll just have to start all processing through I bag file, 
taking care that there is not a core already running which might have 
nodes like rviz already registered.

Best regards,
Armin

-- 
Armin Hornung                              Albert-Ludwigs-Universität
www.informatik.uni-freiburg.de/~hornunga   Dept. of Computer Science
HornungA@informatik.uni-freiburg.de        Humanoid Robots Lab
Tel.: +49 (0)761-203-8010                  Georges-Köhler-Allee 79
Fax : +49 (0)761-203-8007                  D-79110 Freiburg, Germany