Debugging tf problems Tutorial - Typos/errors

asked 2017-03-27 23:47:31 -0500

philglau gravatar image

There seem to be some errors in the 'debugging tf' tutorial, some of which references the previous tf intro tutorials. My guess is this is a hangover from an earlier version of the debugging_tf tutorials. I'm using a 'kinetic' install

1)roslaunch turtle_tf start_debug_demo.launch is launched to demonstrate the problem, but on my kinetic install, this 'start_debug_demo' file seems to reference python files rather than C++. Additionally, later in the tutorial, it's called with roslaunch learning_tf start_debug_demo.launch but the file doesn't exist on the path learning_tf.

Assuming that we should be using the C++ version of the launch file and that the user has just finished the previous learning_tf tutorials in C++, I would recommend copying the existing 'start_demo.launch' file to 'start_debug_demo.launch' and adding some steps in Section 1 for adapting it by indicating that:

<node name="turtle_pointer" pkg="turtle_tf" type="turtle_tf_listener" respawn="false" output="screen" >

should be changed to:

<node name="turtle_pointer" pkg="turtle_tf" type="turtle_tf_listener_debug" respawn="false" output="screen" >

2) Likewise, the CMake file needs to be adjusted in the learning_tf directory and have the following added. This step isn't mentioned and for people new to C++ might be confusing if omitted:

add_executable(turtle_tf_listener_debug src/turtle_tf_listener_debug.cpp)
target_link_libraries(turtle_tf_listener_debug ${catkin_LIBRARIES})

3) on Step 4, it indicates:

$ make
$ roslaunch learning_tf start_debug_demo.launch

I found that this did not work. I believe it should be (as appears to be correctly spelled out in Step 5):

Re-build your package at the top folder of your catkin workspace
$ catkin_make
$ roslaunch learning_tf start_debug_demo.launch

Also, roslaunch learning_tf start_debug_demo.launch will not work unless some steps are taken (as suggested in #1 above) to make sure that a file 'start_debug_demo' exists in the learning_tf directory.

Overall, a nice tutorial. Thank you to those who worked to make it in the first place. Please don't take my proofreading as criticism, it is just to help the next person who comes along the tf tutorial path.

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