What is the use of tf_listener?

Question

I understand that the tf_listener is used to lookup a transform from the tf_tree and then work with that transform to do whatever you want.

So it seems like the tf_listener is just a "tool" to be included in a node which needs the transform between one frame and another. Is there any other functionality of the tf_listener other than lookupTransform? Because the tf_tree exists with or without a tf_listener.

Thank you. (Trying to strengthen my understanding of tf concepts)

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Originally posted by 2ROS0 on ROS Answers with karma: 1133 on 2014-07-07

Post score: 0

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Original comments

Comment by bvbdort on 2014-07-07:
go through the class of tf_listener it gives you more insight ,http://mirror.umd.edu/roswiki/doc/diamondback/api/tf/html/c++/transform__listener_8h_source.html

Comment by gvdhoorn on 2014-07-08:
@bvbdort: that is a really old version of that file. I'm not sure how much (or indeed, if) tf_listener has changed since DiamondBack, but it might be a good idea to look at the Hydro version (ie: 4 releases newer).

Answer 1

The TransformListener is just a tool for to be used inside other libraries. It has two main functions. The first is that it listens for /tf data and caches it locally. And the second is that it exposes the Transformer interface to allow queries against the cached data.

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Originally posted by tfoote with karma: 58457 on 2014-07-07

This answer was ACCEPTED on the original site

Post score: 4