hector_slam tutorial.launch file couldn't launch
Hi, I have pulled and rosmaked hector_slam from : http://wiki.ros.org/hector_slam?distro=groovy
and when try to execute the basic command : roslaunch hector_slam_launch tutorial.launch
I am getting the following errors: but the nodes are in the proper folder of the directories
ERROR: cannot launch node of type [hector_mapping/hector_mapping]: can't locate node [hector_mapping] in package [hector_mapping]
ERROR: cannot launch node of type [hector_trajectory_server/hector_trajectory_server]: can't locate node [hector_trajectory_server] in package [hector_trajectory_server]
ERROR: cannot launch node of type [hector_geotiff/geotiff_node]: can't locate node [geotiff_node] in package [hector_geotiff]