Errata

I followed the second solution (cloning) to the first errata (missing basics directory) and got several error message after catkin_make:
For example:
CMake Error at /opt/ros/jade/share/catkin/cmake/catkin_workspace.cmake:116 (add_subdirectory):
The source directory

/home/ubuntu/catkin_ws/src/basics/code/tortoisebot

does not contain a CMakeLists.txt file.

Same for:
/home/ubuntu/catkin_ws/src/basics/code/cougarbot
/home/ubuntu/catkin_ws/src/basics/code/mapping

In chapter 2 it shows how to make a package my_awesome_code. Then through out the book it refernces a package basics, but NEVER explains that you should create the package basics, or be working in it.

The book assume that you will trouble shoot the problems and sort it all out. In chapter tree there is even a note that it assumes you can create a package and sort it out. Then just leaves you hanging later when you cannot figure out why the package basics is being used or referenced. Is Basics part of ROS? did I miss creating it? Should I create it? Can I use my own?

I can tell you as a reader of many technical books over the past 25 yrs, this is the more frustrating than reading a book that is already out of date when it is published.

All you need to do is rater than create my_awesome_code in chapter two, create package basics.

That's it and I would not have lost a half a day.

To avoid rosrun warning, you should add a queue_size. Line "pub = rospy.Publisher(' counter', Int32)" should be replaced with "pub = rospy.Publisher(' counter', Int32, queue_size = 10)" for example. Actual queue size is up to the user.

The discussion of non-holonomic and holonomic systems is incorrect. See the Wikipedia entry, for example: https://en.wikipedia.org/wiki/Nonholonomic_system.

The chapter should mentioned that a build dependency and runtime dependency on actionlib_msgs need to be included in the package.xml file. This kind of information was mentioned in the previous chapters, but actionlib_msgs is a new concept, and it was not mentioned. This is not consistent.

After the following line:
user@hostname$ cd ~/wanderbot_ws/src

these three command lines are missed:
------------------missed-------------------------------------
user@hostname$ cd ~/wanderbot_ws
user@hostname$ catkin_make
user@hostname$ source devel/setup.bash
-----------------------------------------------------------------

then you can continue with the command in the second line:

user@hostname$catkin_create_pkg wanderbot rospy geometry_msgs sensor_msgs

Shouldn't it be:
"Without this call to 'rate.sleep()' ..."

instead of:
"Without this call to 'rospy.sleep()' ..." ?

There is technically nothing wrong with the logic of the script; however, it doesn't appear to take into account the dynamics of the robot (at least when launched in the turtlebot_world). With a 0.8 meter range threshold and a linear speed of 1 m/s, the robot will crash before it can perceive and react to an object in its path.

.., we can make wander.py executable and run it:

user@hostname$ chmod +x red_light_green_light.py

instead of

user@hostname$ chmod +x wander.py

In Example 8.2:

key_mapping = { 'w': [ 0, 1], 'x': [0, -1],
'a': [-1, 0], 'd': [1, 0],
's': [ 0, 0] }

For 'a' to turn left and 'd' turn right, we should set 'a = [1, 0], d = [-1,0]' since the rotation is counter-clock wise.

There is no the script
keys_to_teleop_with_rates.py

The code there should probably end in an invocation:
moveit_commander.roscpp_shutdown()
Like all the other examples.

When explaining the ROS map images in Figure 9-4, the book writes:

This is because the default size of ROS maps is 200 m × 200 m, with a cell size of 5 cm (that means that the image size is 2,000 x 2,000 pixels).

The correct size is 4,000 x 4,000 pixels.

The given lower and upper bounds for yellow do not capture the line:

lower_yellow = numpy.array([50, 50, 170])
upper_yellow = numpy.array([255, 255, 190])

Instead I successfully used:

lower_yellow = numpy.array([20, 100, 100])
upper_yellow = numpy.array([30, 255, 255])

Should be:

with sm:
sm.add(...)
sm.add(...)

instead of:

with sm:
StateMachine.add(...)
StateMachine.add(...)

The paragraph starts out: "Because the models directory is referenced by the GAZEBO_MODEL_PATH environment variable...". But the "models" directory isn't referenced by that variable, the containing "stockroom_bot" directory is the lowest directory defined in that variable. The directory defined in the "sb" alias should include the "models" subdirectory -- otherwise the later gazebo command (on page 236) will fail.

The callback function:

def save_value(value)
with lock:
angle = value * 2 * pi / 100.0

will assigning the new value to the local variable "angle" which will not be accessible in the main loop. The function needs to declare that "angle" is a global variable::

def save_value(value)
global angle
with lock:
angle = value * 2 * pi / 100.0

End of the last line is:
"... [1.0, 0.0]}]} -1' ..."

Should be:
"... [1.0, 0.0]}]}' -1 ..."
like on page 334.