Hi all, I'm trying to follow the tutorial on transform listener: http://www.ros.org/wiki/tf/Tutorials/Writing%20a%20tf%20listener%20(C%2B%2B) I'm trying to use it with simulated pr2 and gmapping to determine location of the robot relative to the map. What I'm getting is following message: [ERROR] 4546.007000467: Could not find a connection between '/map' and '/base_footprint' because they are not part of the same tree.Tf has two or more unconnected trees. When trying to transform between /map and /base_footprint. although, rviz shows the transforms and connections just fine, tf_echo outputs the transforms as well and tf_view prints out just one tree (attached). Any hints on what might be the problem would be very appreciated. Michal