altitude_histogram.py

import numpy as np
import matplotlib.mlab as mlab
import matplotlib.pyplot as plt


# Open the file with all the airports and read every line
data = open("airports.dat", "r").readlines()

# make an array to store the final data
final_data = []

# go through each row and extract the airport altitude
for row in data:
	row_items = row.split(",") # split by the comma
	final_data.append(float(row_items[8]))
  

num_bins = 50

fig, ax = plt.subplots()

# the histogram of the data
n, bins, patches = ax.hist(final_data, num_bins, normed=0)

# add a 'best fit' lin
ax.set_xlabel('Altitude')
ax.set_ylabel('Number of Airports')
ax.set_title(r'Histogram of Elevations of Airports')

# Tweak spacing to prevent clipping of ylabel
fig.tight_layout()
plt.show()