Hi Eunchul,
The reset_time topic is a vestige of debugging code in tf which was not
cleaned out.  It is in the process of being phased out and it won't help
you.

I would suggest that you follow the advice of the warning """Please turn the
[ros.gmapping.message_
notifier] rosconsole logger to DEBUG for more information."""  This will
tell you exactly what the problem is transforming your data.  With that
error we can help you debug the problem.

Tully

On Thu, Nov 18, 2010 at 10:01 AM, Eitan Marder-Eppstein <
eitan@willowgarage.com> wrote:

> Eunchul Jeon,
>
> It seems likely that something is wrong in your tf tree when trying to
> transform points from the laser frame to the odometric frame. Can you use a
> tool like view_frames or tf_echo to find out what your tree looks like? In
> particular you should be able to run tf_echo laser odom successfully before
> expecting gmapping to work.
>
> Hope this helps,
>
> Eitan
>
> On Thu, Nov 18, 2010 at 5:01 AM, eunchul Jeon <jsharp83@gmail.com> wrote:
>
>> Hi, I'm Eunchul Jeon,
>>
>> I saw following warning when I run the rosrun gmapping slam_gmapping
>> scan:=base_scan
>>
>> [ WARN] [1290084259.016741027]: Message from [/hokuyo_node] has a
>> non-fully-qualified frame_id [laser]. Resolved locally to [/laser].  This is
>> will likely not work in multi-robot systems.  This message will only print
>> once.
>> [ WARN] [1290084273.997493021]: MessageFilter [target=/odom ]: Dropped
>> 100.00% of messages so far. Please turn the [ros.gmapping.message_notifier]
>> rosconsole logger to DEBUG for more information.
>>
>> and I ran the roswtf command, and saw following warning
>>
>> WARNING The following node subscriptions are unconnected:
>>  * /rviz_1290083985383805192:
>>    * /scan
>>    * /reset_time
>>  * /slam_gmapping:
>>    * /reset_time
>>  * /LaserListener:
>>    * /base_scan1
>>
>> Maybe I need to connect reset_time node but I can't find any information
>> about that.
>>
>> Thank you in advance your help.
>>
>> --
>> ================================================
>> Eunchul Jeon
>>
>> M.S. Student, Intelligent Systems and Neurobotics lab,
>> Dept. Computer Science, KAIST
>> Science town, Daejeon, 305-701, South Korea
>> TEL: 82 42 350 3580
>> E-mail: jsharp@kaist.ac.kr, jsharp83@gmail.com
>> Homepage: http://isnl.kaist.ac.kr
>> ================================================
>>
>> _______________________________________________
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>>
>>
>
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>


-- 
Tully Foote
Systems Engineer
Willow Garage, Inc.
tfoote@willowgarage.com
(650) 475-2827