Remove Tf2 time tutorials for Python (#4384)

* Small update for language in tf2 static transforms.

* Small language fixups in tf2 broadcaster tutorials.

* Small language updates in Writing a tf2 listener.

* Small clarification in Add-a-frame tutorials.

* Small updates to the Learning-about-tf2-and-time-cpp tutorial.

* Remove the python tf2 tutorials.

They have not worked for a very long time, and in point of
fact with the current tf2_py code, they cannot work.
Remove them until the time we actually fix the tf2_py
code, at which point we can reintroduce them.

Signed-off-by: Chris Lalancette <[email protected]>
(cherry picked from commit cb0e0be)

# Conflicts:
#	source/Tutorials/Intermediate/Tf2/Adding-A-Frame-Cpp.rst
#	source/Tutorials/Intermediate/Tf2/Adding-A-Frame-Py.rst
#	source/Tutorials/Intermediate/Tf2/Learning-About-Tf2-And-Time-Py.rst
#	source/Tutorials/Intermediate/Tf2/Time-Travel-With-Tf2-Py.rst
#	source/Tutorials/Intermediate/Tf2/Writing-A-Tf2-Broadcaster-Cpp.rst
#	source/Tutorials/Intermediate/Tf2/Writing-A-Tf2-Broadcaster-Py.rst
#	source/Tutorials/Intermediate/Tf2/Writing-A-Tf2-Listener-Cpp.rst
#	source/Tutorials/Intermediate/Tf2/Writing-A-Tf2-Listener-Py.rst

source/Concepts/Intermediate/About-Tf2.rst

@@ -56,8 +56,8 @@ If you want to define static transforms in your tf2 tree, take a look at the "Wr
 You can also learn how to add fixed and dynamic frames to your tf2 tree in the "Adding a frame" :doc:`(Python) <../../Tutorials/Intermediate/Tf2/Adding-A-Frame-Py>` :doc:`(C++) <../../Tutorials/Intermediate/Tf2/Adding-A-Frame-Cpp>` tutorial.
 
 Once you are finished with the basic tutorials, you can move on to learn about tf2 and time.
-The tf2 and time tutorial :doc:`(Python) <../../Tutorials/Intermediate/Tf2/Learning-About-Tf2-And-Time-Py>` :doc:`(C++) <../../Tutorials/Intermediate/Tf2/Learning-About-Tf2-And-Time-Cpp>` teaches the basic principles of tf2 and time.
-The advanced tutorial about tf2 and time :doc:`(Python) <../../Tutorials/Intermediate/Tf2/Time-Travel-With-Tf2-Py>` :doc:`(C++) <../../Tutorials/Intermediate/Tf2/Time-Travel-With-Tf2-Cpp>` teaches the principles of time traveling with tf2.
+The tf2 and time tutorial :doc:`(C++) <../../Tutorials/Intermediate/Tf2/Learning-About-Tf2-And-Time-Cpp>` teaches the basic principles of tf2 and time.
+The advanced tutorial about tf2 and time :doc:`(C++) <../../Tutorials/Intermediate/Tf2/Time-Travel-With-Tf2-Cpp>` teaches the principles of time traveling with tf2.
 
 Paper
 -----

source/Tutorials/Intermediate/Tf2/Adding-A-Frame-Cpp.rst

@@ -184,7 +184,11 @@ Finally, add the ``install(TARGETS…)`` section so ``ros2 run`` can find your e
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Now let's create a launch file for this example.
+<<<<<<< HEAD
 With your text editor, create a new file called ``launch/turtle_tf2_fixed_frame_demo.launch.py``, and add the following lines:
+=======
+With your text editor, create a new file called ``turtle_tf2_fixed_frame_demo_launch.py`` in the ``src/learning_tf2_cpp/launch`` directory, and add the following lines:
+>>>>>>> cb0e0be2 (Remove Tf2 time tutorials for Python (#4384))
 
 .. code-block:: python
 
@@ -473,7 +477,11 @@ Finally, add the ``install(TARGETS…)`` section so ``ros2 run`` can find your e
 2.3 Write the launch file
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
+<<<<<<< HEAD
 To test this code, create a new launch file ``launch/turtle_tf2_dynamic_frame_demo.launch.py`` and paste the following code:
+=======
+To test this code, create a new launch file ``turtle_tf2_dynamic_frame_demo_launch.py`` in the ``src/learning_tf2_cpp/launch`` directory and paste the following code:
+>>>>>>> cb0e0be2 (Remove Tf2 time tutorials for Python (#4384))
 
 .. code-block:: python
 

source/Tutorials/Intermediate/Tf2/Adding-A-Frame-Py.rst

@@ -160,7 +160,11 @@ Add the following line between the ``'console_scripts':`` brackets:
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Now let's create a launch file for this example.
+<<<<<<< HEAD
 With your text editor, create a new file called ``launch/turtle_tf2_fixed_frame_demo.launch.py``, and add the following lines:
+=======
+With your text editor, create a new file called ``turtle_tf2_fixed_frame_demo_launch.py`` in the ``src/learning_tf2_py/launch`` directory, and add the following lines:
+>>>>>>> cb0e0be2 (Remove Tf2 time tutorials for Python (#4384))
 
 .. code-block:: python
 
@@ -204,7 +208,6 @@ The last part of the code will add our fixed ``carrot1`` frame to the turtlesim
         name='fixed_broadcaster',
     ),
 
-
 1.4 Build
 ~~~~~~~~~
 
@@ -427,7 +430,11 @@ Add the following line between the ``'console_scripts':`` brackets:
 2.3 Write the launch file
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
+<<<<<<< HEAD
 To test this code, create a new launch file ``launch/turtle_tf2_dynamic_frame_demo.launch.py`` and paste the following code:
+=======
+To test this code, create a new launch file ``turtle_tf2_dynamic_frame_demo_launch.py`` in the ``src/learning_tf2_py/launch`` directory and paste the following code:
+>>>>>>> cb0e0be2 (Remove Tf2 time tutorials for Python (#4384))
 
 .. code-block:: python
 

source/Tutorials/Intermediate/Tf2/Learning-About-Tf2-And-Time-Cpp.rst

@@ -21,19 +21,19 @@ Background
 ----------
 
 In previous tutorials, we recreated the turtle demo by writing a :doc:`tf2 broadcaster <Writing-A-Tf2-Broadcaster-Cpp>` and a :doc:`tf2 listener <Writing-A-Tf2-Listener-Cpp>`.
-We also learned how to :doc:`add a new frame to the transformation tree <./Adding-A-Frame-Cpp>` and learned how tf2 keeps track of a tree of coordinate frames.
+We also learned how to :doc:`add a new frame to the transformation tree <Adding-A-Frame-Cpp>` and learned how tf2 keeps track of a tree of coordinate frames.
 This tree changes over time, and tf2 stores a time snapshot for every transform (for up to 10 seconds by default).
 Until now we used the ``lookupTransform()`` function to get access to the latest available transforms in that tf2 tree, without knowing at what time that transform was recorded.
 This tutorial will teach you how to get a transform at a specific time.
 
 Tasks
 -----
 
-1 tf2 and time
-^^^^^^^^^^^^^^
+1 Update the listener node
+^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-So let's go back to where we ended in the :doc:`adding a frame tutorial <./Adding-A-Frame-Cpp>`.
-Go to ``learning_tf2_cpp`` package.
+Let's go back to where we ended in the :doc:`adding a frame tutorial <Adding-A-Frame-Cpp>`.
+Go to the ``learning_tf2_cpp`` package.
 Open ``turtle_tf2_listener.cpp`` and take a look at the ``lookupTransform()`` call:
 
 .. code-block:: C++
@@ -73,7 +73,7 @@ You will notice that it fails and outputs something similar to this:
 
 .. code-block:: console
 
-   [INFO] [1629873136.345688064] [listener]: Could not transform turtle1 to turtle2: Lookup would
+   [INFO] [1629873136.345688064] [listener]: Could not transform turtle2 to turtle1: Lookup would
    require extrapolation into the future.  Requested time 1629873136.345539 but the latest data
    is at time 1629873136.338804, when looking up transform from frame [turtle1] to frame [turtle2]
 
@@ -84,8 +84,8 @@ Firstly, each listener has a buffer where it stores all the coordinate transform
 Secondly, when a broadcaster sends out a transform, it takes some time before that transform gets into the buffer (usually a couple of milliseconds).
 As a result, when you request a frame transform at time "now", you should wait a few milliseconds for that information to arrive.
 
-2 Wait for transforms
-^^^^^^^^^^^^^^^^^^^^^
+2 Fix the listener node
+^^^^^^^^^^^^^^^^^^^^^^^
 
 tf2 provides a nice tool that will wait until a transform becomes available.
 You use this by adding a timeout parameter to ``lookupTransform()``.
@@ -103,8 +103,8 @@ To fix this, edit your code as shown below (add the last timeout parameter):
 The ``lookupTransform()`` can take four arguments, where the last one is an optional timeout.
 It will block for up to that duration waiting for it to timeout.
 
-3 Checking the results
-^^^^^^^^^^^^^^^^^^^^^^
+3 Check the results
+^^^^^^^^^^^^^^^^^^^
 
 You can now run the launch file.
 

source/Tutorials/Intermediate/Tf2/Tf2-Main.rst

@@ -27,9 +27,7 @@ If you want to learn both C++ and Python, you should go through the tutorials on
    Writing-A-Tf2-Listener-Cpp
    Adding-A-Frame-Py
    Adding-A-Frame-Cpp
-   Learning-About-Tf2-And-Time-Py
    Learning-About-Tf2-And-Time-Cpp
-   Time-Travel-With-Tf2-Py
    Time-Travel-With-Tf2-Cpp
    Debugging-Tf2-Problems
    Quaternion-Fundamentals
@@ -65,12 +63,12 @@ Learning tf2
 
    This tutorial teaches you how to add an extra fixed frame to tf2.
 
-#. Using time :doc:`(Python) <Learning-About-Tf2-And-Time-Py>` :doc:`(C++) <Learning-About-Tf2-And-Time-Cpp>`.
+#. Using time :doc:`(C++) <Learning-About-Tf2-And-Time-Cpp>`.
 
    This tutorial teaches you to use the timeout in ``lookup_transform`` function to
    wait for a transform to be available on the tf2 tree.
 
-#. Traveling in time :doc:`(Python) <./Time-Travel-With-Tf2-Py>` :doc:`(C++) <./Time-Travel-With-Tf2-Cpp>`.
+#. Traveling in time :doc:`(C++) <./Time-Travel-With-Tf2-Cpp>`.
 
    This tutorial teaches you about advanced time travel features of tf2.
 

source/Tutorials/Intermediate/Tf2/Writing-A-Tf2-Broadcaster-Cpp.rst

@@ -246,7 +246,12 @@ Finally, add the ``install(TARGETS…)`` section so ``ros2 run`` can find your e
 ^^^^^^^^^^^^^^^^^^^^^^^
 
 Now create a launch file for this demo.
+<<<<<<< HEAD
 With your text editor, create a new file called ``turtle_tf2_demo.launch.py`` in the ``launch`` folder, and add the following lines:
+=======
+Create a ``launch`` folder in the ``src/learning_tf2_cpp`` directory.
+With your text editor, create a new file called ``turtle_tf2_demo_launch.py`` in the ``launch`` folder, and add the following lines:
+>>>>>>> cb0e0be2 (Remove Tf2 time tutorials for Python (#4384))
 
 .. code-block:: python
 

source/Tutorials/Intermediate/Tf2/Writing-A-Tf2-Broadcaster-Py.rst

@@ -252,7 +252,11 @@ Add the following line between the ``'console_scripts':`` brackets:
 
 Now create a launch file for this demo.
 Create a ``launch`` folder in the ``src/learning_tf2_py`` directory.
+<<<<<<< HEAD
 With your text editor, create a new file called ``turtle_tf2_demo.launch.py`` in the ``launch`` folder, and add the following lines:
+=======
+With your text editor, create a new file called ``turtle_tf2_demo_launch.py`` in the ``launch`` folder, and add the following lines:
+>>>>>>> cb0e0be2 (Remove Tf2 time tutorials for Python (#4384))
 
 .. code-block:: python
 

source/Tutorials/Intermediate/Tf2/Writing-A-Tf2-Listener-Cpp.rst

@@ -274,7 +274,11 @@ Finally, add the ``install(TARGETS…)`` section so ``ros2 run`` can find your e
 2 Update the launch file
 ^^^^^^^^^^^^^^^^^^^^^^^^
 
+<<<<<<< HEAD
 Open the launch file called ``turtle_tf2_demo.launch.py`` with your text editor, add two new nodes to the launch description, add a launch argument, and add the imports.
+=======
+Open the launch file called ``turtle_tf2_demo_launch.py`` in the ``src/learning_tf2_cpp/launch`` directory with your text editor, add two new nodes to the launch description, add a launch argument, and add the imports.
+>>>>>>> cb0e0be2 (Remove Tf2 time tutorials for Python (#4384))
 The resulting file should look like:
 
 .. code-block:: python

source/Tutorials/Intermediate/Tf2/Writing-A-Tf2-Listener-Py.rst

@@ -228,7 +228,11 @@ Add the following line between the ``'console_scripts':`` brackets:
 2 Update the launch file
 ^^^^^^^^^^^^^^^^^^^^^^^^
 
+<<<<<<< HEAD
 Open the launch file called ``turtle_tf2_demo.launch.py`` with your text editor, add two new nodes to the launch description, add a launch argument, and add the imports.
+=======
+Open the launch file called ``turtle_tf2_demo_launch.py`` in the ``src/learning_tf2_py/launch`` directory with your text editor, add two new nodes to the launch description, add a launch argument, and add the imports.
+>>>>>>> cb0e0be2 (Remove Tf2 time tutorials for Python (#4384))
 The resulting file should look like:
 
 .. code-block:: python

source/Tutorials/Intermediate/Tf2/Writing-A-Tf2-Static-Broadcaster-Cpp.rst

@@ -394,14 +394,14 @@ This tutorial aimed to show how ``StaticTransformBroadcaster`` can be used to pu
 In your real development process you shouldn't have to write this code yourself and should use the dedicated ``tf2_ros`` tool to do so.
 ``tf2_ros`` provides an executable named ``static_transform_publisher`` that can be used either as a commandline tool or a node that you can add to your launchfiles.
 
-Publish a static coordinate transform to tf2 using an x/y/z offset in meters and roll/pitch/yaw in radians.
-In our case, roll/pitch/yaw refers to rotation about the x/y/z-axis, respectively.
+The following command publishes a static coordinate transform to tf2 using an x/y/z offset in meters and roll/pitch/yaw in radians.
+In ROS 2, roll/pitch/yaw refers to rotation about the x/y/z-axis, respectively.
 
 .. code-block:: console
 
     ros2 run tf2_ros static_transform_publisher --x x --y y --z z --yaw yaw --pitch pitch --roll roll --frame-id frame_id --child-frame-id child_frame_id
 
-Publish a static coordinate transform to tf2 using an x/y/z offset in meters and quaternion.
+The following command publishes a static coordinate transform to tf2 using an x/y/z offset in meters and roll/pitch/yaw as a quaternion.
 
 .. code-block:: console
 

source/Tutorials/Intermediate/Tf2/Writing-A-Tf2-Static-Broadcaster-Py.rst

@@ -413,14 +413,14 @@ This tutorial aimed to show how ``StaticTransformBroadcaster`` can be used to pu
 In your real development process you shouldn't have to write this code yourself and should use the dedicated ``tf2_ros`` tool to do so.
 ``tf2_ros`` provides an executable named ``static_transform_publisher`` that can be used either as a commandline tool or a node that you can add to your launchfiles.
 
-Publish a static coordinate transform to tf2 using an x/y/z offset in meters and roll/pitch/yaw in radians.
-In our case, roll/pitch/yaw refers to rotation about the x/y/z-axis, respectively.
+The following command publishes a static coordinate transform to tf2 using an x/y/z offset in meters and roll/pitch/yaw in radians.
+In ROS 2, roll/pitch/yaw refers to rotation about the x/y/z-axis, respectively.
 
 .. code-block:: console
 
     ros2 run tf2_ros static_transform_publisher --x x --y y --z z --yaw yaw --pitch pitch --roll roll --frame-id frame_id --child-frame-id child_frame_id
 
-Publish a static coordinate transform to tf2 using an x/y/z offset in meters and quaternion.
+The following command publishes a static coordinate transform to tf2 using an x/y/z offset in meters and roll/pitch/yaw as a quaternion.
 
 .. code-block:: console