tf_echo argument inconsistency

[gaya-]

In tf_echo the source frame and target frame are mixed up, namely, the parent frame is called the "source frame" and the child is the "target", whereas everywhere else in TF and TF2 the convention is the opposite.

E.g. here the first argument is called "source_frameid" but it actually is the target frame id.

This inconsistency is really confusing, especially as it's not just the tf_echo but also the TF tutorials use the convention opposite from the actual implementation.

Should I make a PR for tf_echo and fix the tutorials afterwards?

[tfoote]

Duplicate: #108

[gaya-]

My bad, only checked the list of open issues.

Using "parent_frame" and "child_frame" instead of "source" and "target" might help to alleviate the confusion in the future...

[ros-discourse]

This issue has been mentioned on ROS Discourse. There might be relevant details there:

https://discourse.ros.org/t/nomenclature-of-tf-echo-and-tf-listener/36985/7