Missing connection between /map and /base_link

edit

Hi at all,

I am very new to ROS. After working out the tutorials and the Book "ROS by example" I got the following error, when running rviz with my personal robot.model:

> Waiting on transform from /base_link to /map to become available before running costmap, tf error: Could not find a connection between '/map' and '/base_link' because they are not part of the same tree.Tf has two or more unconnected trees. <<<

In my urdf File I have got only base and a link to a Laser_link, which is not used yet.

I looked through many files comparing mine with the turtlebot-files. I dont understand where the link between base_link and map is made, I believe it is in the move_base but I really dont know. If it helps I can send the content of files but dont know which one.

Hope that someone here can help me.

Thanks and best wishes

Michael, Berlin, Germany

EDIT

Sorry for asking again. I get the error in the console when running roslaunch myrobot fake_turtlebot.launch, not in rviz, si the error message doesnt depend on my settings in rviz. I do this too find out and compare my file with turtlebot-tutorial, why my robot isnt operating correct, eg. when I want to run move_base and click in the map to define a goal. When I run myrobot myrobot.lauch the rviz shows the thin blue line as path to the goal correctly, but is moving somewhere in the wrong direction with flashing the red lines.