18. Common Questions
GitHub and Markdown
If you are unfamiliar with GitHub , Udacity has a brief GitHub tutorial to get you started. Udacity also provides a more detailed free course on git and GitHub.
To learn about REAMDE files and Markdown, Udacity provides a free course on READMEs, as well.
GitHub also provides a tutorial about creating Markdown files.
Common Questions
Below is a list of common student questions asked for this lesson. This list is created and answered by students. A special thanks to one of our students, Adam Malpass (@tokyo_adam in our Slack community) for helping compile and curate this list!
Question: How do I change the resolution of the simulator in Windows?
Answer: ctrl + double click
Question: I am using Linux with ROS installed and getting ImportError
whenever I am running code from Project 1
Answer: Please check this link here.
Question: How to create a video output of the Rover in Project 1?
Answer: You could try and setup MoviePy to generate a video from the saved still images, but it is much easier just to use a screen recording program, e.g. Quicktime, Camtasia, etc, to directly capture your screen! You can then (optionally) use a program like Handbrake to encode and compress the video file.
Question: My world map looks mirrored, what can be the issue?
Answer: Try swapping your x-y coordinates or use the following at the end:
Rover.worldmap = np.fliplr(Rover.worldmap)
Rover.worldmap = np.rot90(Rover.worldmap)
Legacy Issues:
The following issues have been solved in the repository.
Question: Error when running 'Read in saved data and ground truth map of the world' block in Jupyter notebook:
During handling of the above exception, another exception occurred:
KeyError Traceback (most recent call last)
<ipython-input-63-bd52d33fb6f4> in <module>()
3 # Change this path to your data directory
4 df = pd.read_csv(‘../johnsRover/robot_log.csv’)
----> 5 csv_img_list = df[“Path”].tolist() # Create list of image pathnames
6 # Read in ground truth map and create a 3-channel image with it
7 ground_truth = mpimg.imread(‘../calibration_images/map_bw.png’)
Answer:
You're getting this error since the delimiter in the csv file is currently a ',' and not ';' in pd.read_csv(). Alternatively this issue has been fixed in the project repo now.
Question: How to solve an error like this (related to needing ffmpeg.py) when creating the MoviePy video in Project 1:
NeedDownloadError Traceback (most recent call last)
/Users/nagen/anaconda/envs/RoboND/lib/python3.5/site-packages/imageio/plugins/ffmpeg.py in get_exe()
81 exe = get_remote_file('ffmpeg/' + FNAME_PER_PLATFORM[plat],
---> 82 auto=False)
83 os.chmod(exe, os.stat(exe).st_mode | stat.S_IEXEC) # executable
/Users/nagen/anaconda/envs/RoboND/lib/python3.5/site-packages/imageio/core/fetching.py in get_remote_file(fname, directory, force_download, auto)
101 if not auto:
--> 102 raise NeedDownloadError()```
**Answer:** Add the following lines at the top of the code cell to fix it:
First need to install ffmpeg dependency
import imageio
imageio.plugins.ffmpeg.download()
```
(NB: If you download the latest version of the project repo then this dependency has now been added so this issue should not occur).