how to change the shape of a contour in matplotlib

Question

I am using contour or contourf in matplotlib

And the data is a 2D array with values in, like this:

1 2 3 3 3
2 3 3 4 1
2 3 4 5 6
...

The result I got is as below.

It is like a square, while actually, the y extent is 600+ and x extent is only 350. So the figure should look like a rectangle, not a square.

But I looked into the arguments in contour and contourf, there is no argument about changing the shape of the contour, or changing the length of the axis.

for Adobe, here is the simplified code of my case:

import matplotlib.pyplot as plt

m = [[1,2,3,4],
[2,3,4,5],
[2,2,1,5]]

print m
plt.contourf(m)
plt.show()

Then, in this situation, how to use ax.axis()?

Answer 1

Probably You want to set equal scale:

ax.axis('equal')

Edit

Here's Your code:

#!/usr/bin/python3

from matplotlib import pyplot as plt

m = [[1,2,3,4],
     [2,3,4,5],
     [2,2,1,5]]

fig = plt.figure()
ax = fig.add_subplot(111)

ax.contourf(m)
ax.axis('equal')

fig.savefig("equal.png")

matplotlib has three interfaces. Here's the same code written to utilize each of them:

1. machine-state:

   import matplotlib.pyplot as plt
   import numpy as np
   x = np.arange(0, 10, 0.2)
   y = np.sin(x)
   plt.plot(x, y)
   plt.show()
   

2. pylab:

   from pylab import *
   x = arange(0, 10, 0.2)
   y = sin(x)
   plot(x, y)
   show()
   

3. object-oriented:

   import matplotlib.pyplot as plt
   import numpy as np
   x = np.arange(0, 10, 0.2)
   y = np.sin(x)
   fig = plt.figure()
   ax = fig.add_subplot(111)
   ax.plot(x, y)
   plt.show()
   

I prefer object-oriented interface: it gives full control on what is going on. I cited solution for that one.