Hi Eitan, Thanks for your reply. I tried the "RVIZ with navigation stack" tutorial. The map was displayed properly, and I also added the pose array. But I was unable to display the polygon showing the robot footprint. RVIZ warns me that there are no messages received in move_base/local_costmap/robot_footprint. There are also no messages received for move_base/local_costmap/obstacles or inflated obstacles. And indeed, when I 'rostopic echo' robot_footprint, I get no messages. At this point, I went through all my files again and noticed that in 'costmap_common_params.yaml', I had written the robot footprint values in centimeters and not in meters. I corrected this, so now the file looks like: Costmap_common_params.yaml obstacle_range: 2.5 raytrace_range: 3.0 footprint: [[0.275,0.325], [-0.275,0.325], [-0.275,-0.325], [0.275,-0.325]] observation_sources: laser_scan_sensor transform_tolerance: 2.0 laser_scan_sensor: {sensor_frame: laser, data_type: LaserScan, topic: /scan, marking: true, clearing: true} inflation_radius: 0.55 I ran the simulation again. And the errors are still the same with no differences. So I believe that was not the problem anyway. When I run the Rviz with navigation goals tutorial, I get the warning: [ INFO] [1291168915.975023299]: Received a 384 X 832 map at 0.100000 m/pix [ WARN] [1291168933.842753803]: The origin for the sensor at (0.10, -0.00, 0.00) is out of map bounds. So, the costmap cannot raytrace for it. [ WARN] [1291168986.842490604]: The origin for the sensor at (0.10, -0.00, 0.00) is out of map bounds. So, the costmap cannot raytrace for it. At this point, roswtf gives me: roswtf: shanker@DFKIShankerMBpro:~/Workspace/nifti/initial/subarchitectures/navigation.sa$ roswtf Loaded plugin tf.tfwtf Package: navigation.sa ================================================================================ Static checks summary: No errors or warnings ================================================================================ Beginning tests of your ROS graph. These may take awhile... analyzing graph... ... done analyzing graph running graph rules... ... done running graph rules running tf checks, this will take a second... ... tf checks complete Online checks summary: Found 2 warning(s). Warnings are things that may be just fine, but are sometimes at fault WARNING The following node subscriptions are unconnected: * /amcl: * /reset_time * /rviz_1291167645895723737: * /reset_time * /move_base: * /move_base_simple/goal * /move_base/cancel * /reset_time * /tf_message WARNING The following nodes are unexpectedly connected: * /driver->/rosout (/rosout) * /move_base->/rosout (/rosout) * /initialpose->/rosout (/rosout) * /sicklms->/rosout (/rosout) * /amcl->/rosout (/rosout) * /rviz_1291167645895723737->/rosout (/rosout) * /map_server->/rosout (/rosout) * /tflaserlink->/rosout (/rosout) * /odomesub->/rosout (/rosout) I will check localization without navigation and post my results. Thanks for your help! Shanker -- View this message in context: http://ros-users.122217.n3.nabble.com/Navigation-stack-Error-Aborting-because-a-valid-plan-could-not-be-found-tp1956004p1996539.html Sent from the ROS-Users mailing list archive at Nabble.com.