Visualizing the filesystem tree using a polar bar

We want to show in this recipe how to solve a "real-world" task—how to use matplotlib to visualize our directory occupancy.

In this recipe we will learn how to visualize a filesystem tree with relative sizes.

Getting ready

We all have big hard drives that sometimes contain stuff that we usually forget about. It would be nice to see what is inside such a directory, and what the biggest file inside is.

Although there are many more sophisticated and elaborate software products for this job, we want to demonstrate how this is achievable using Python and matplotlib.

How to do it...

Let's perform the following steps:

1. Implement a few helper functions to deal with folder discovery and internal data structures.

2. Implement the main function, draw(), that does the plotting.

3. Implement the main program body that verifies the user input arguments:

   import os
   import sys
   
   import matplotlib.pyplot as plt
   import matplotlib.cm as cm
   import numpy as np
   
   def build_folders...