[ros-users] How to parse the bag file?

My advisor gave me a bag file for a pr2 robot, which includes three kinds of
topic, namely sensor_msgs/pointcloud, sensor_msgs/pointcloud2 and
tf/tfmessage. 
I want to get the robot motion information and the obstacle position
information. From the tf document I can get two kinds of information. One
kind is of a tree  to introduce the relationship of different links. But the
other kind like this:
transforms
    [0]
        header
            seq: 0
            stamp: 1274768649205000409
                secs: 1274768649
                nsecs: 205000409
            frame_id: /odom_combined
        child_frame_id: /base_footprint
        transform
            translation
                x: 2.12986805655
                y: -0.140524320055
                z: 0.0
            rotation
                x: 0.00490979815527
                y: 0.00847065476276
                z: 0.721995381834
                w: 0.691828599077
I want to know  how to use the translation and rotation operations.
Another question is about the sensor_msgs/pointcloud topic. In the
sensor_msgs/pointcloud document, I don't know how to use the index, distance
and timestamp channel. I want to know how to find the help document.
Thank you.
-- 
View this message in context: http://ros-users.122217.n3.nabble.com/How-to-parse-the-bag-file-tp942523p942523.html
Sent from the ROS-Users mailing list archive at Nabble.com.

------------------------------------------------------------------------------
This SF.net email is sponsored by Sprint
What will you do first with EVO, the first 4G phone?
Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first
_______________________________________________
ros-users mailing list
ros-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/ros-users