[ros-users] CSV with time from bag files

[cuenta altas]

Hi Cedric,

I don't know if what you say applies here. If I understood you well when you
mention 'testing software', that would be achieved using 'rosbag play'. If
you are using 'rostopic echo' you'll just get a bunch of data printed on
screen (or to a text file).

Miguel.

2010/6/9 Cedric Pradalier <cedric.pradalier at mavt.ethz.ch>

> On 06/09/2010 04:31 PM, Jeremy Leibs wrote:
> > Agreed.  I was also surprised to find it didn't print bag time.  I
> > created ticket: https://code.ros.org/trac/ros/ticket/2780 to track
> > this issue.
> >
>
> I actually implemented a playback functionality for another middleware
> some time ago, and I had put that as an option.
> In some context, one would want to have the time at which the data was
> recorded (for plotting for instance).
> On the other hand, if you test some software, then it's better to put
> the writing time, to have a feeling of real-time.
>
> Then I also had an option for time scaling (fast-forward or
> slow-motion). Then again, the choice of old time-stamp, write time-stamp
> becomes tricky, especially if you introduce a pause mechanism in the
> playback.
>
> Even without the special features above, I think both type of timestamp
> are sometimes useful, and only a command-line option can select between
> them.
>
> HTH
>
> > On Wed, Jun 9, 2010 at 2:14 AM, Miguel Prada<miguel.register at gmail.com>
>  wrote:
> >
> >> Hi Jeremy,
> >>
> >> Thanks for the tip. That's exactly what I've been doing after writing to
> the list and it works great.
> >>
> >> However, shouldn't rostopic output the bagfile's timestamps when echoing
> from a bagfile? I find it much more reasonable than having to
> programatically read the data using python to achieve this result. Am I
> missing some important reason for rostopic echo to behave this way?
> >>
> >> Miguel.
> >>
> >> El 09/06/2010, a las 10:33, Jeremy Leibs escribió:
> >>
> >>
> >>> Assuming you are still using boxturtle, rosrecord has a rosrecord.py
> >>> programmatic API
> >>>
> >>> Take a look at:
> >>>
> >>> http://www.ros.org/wiki/rosrecord#rosrecord.py
> >>>
> >>> It should be fairly straight forward to write a small program which
> >>> opens the bag and prints exactly what you want.
> >>>
> >>> On Wed, Jun 9, 2010 at 1:29 AM, Miguel Prada<miguel.register at gmail.com>
>  wrote:
> >>>
> >>>> Hi,
> >>>>
> >>>> I want to manipulate some data from a bag file with a spreadsheet. I'm
> exporting from the bag to CSV using 'rostopic echo -p -b BAGFILE TOPIC>>
>  file.csv' but I just realised that the time field you get from doing that
> is the time corresponding to when rostopic is run, not the time stored in
> the bag file. That means that if I use this method to output messages in one
> topic and then repeat for another topic (e.g. controller commands and robot
> positions) the time fields on both CSV files are of no use at all to merge
> the data in those two files.
> >>>>
> >>>> I tried using 'rostopic echo -p -b BAGFILE -a>>  file.csv' to print
> all topics at once, but the output is quite messed up and doesn't clearly
> state which data corresponds to which topic.
> >>>>
> >>>> Does anyone have any suggestion on how should I proceed with this?
> >>>>
> >>>> Miguel.
> >>>>
> >>>> _______________________________________________
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> >>>>
> >>>>
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>
>
> --
> Dr. Cedric Pradalier
> http://www.asl.ethz.ch/people/cedricp
>
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