Matplotlib.pyplot.contourf() in Python

Last Updated : 21 Apr, 2020

Matplotlib is a library in Python and it is numerical – mathematical extension for NumPy library. Pyplot is a state-based interface to a Matplotlib module which provides a MATLAB-like interface.

matplotlib.pyplot.contourf() Function

The contourf() function in pyplot module of matplotlib library is used to plot contours. But contourf draw filled contours, while contourf draws contour lines.

Syntax: matplotlib.pyplot.contourf(\*args, data=None, \*\*kwargs)

Parameters: This method accept the following parameters that are described below:

X, Y: These parameter are the coordinates of the values in Z.

Z : This parameter is the height values over which the contour is drawn.

levels : This parameter is used to determine the numbers and positions of the contour lines / regions.

Returns: This returns the following:

c :This returns the QuadContourSet.

Below examples illustrate the matplotlib.pyplot.contourf() function in matplotlib.pyplot:

Example #1:

# Implementation of matplotlib function 
import numpy as np 
import matplotlib.pyplot as plt 
from numpy import ma 
from matplotlib import ticker, cm 
   
N = 1000
x = np.linspace(-6.0, 6.0, N) 
y = np.linspace(-7.0, 7.0, N) 
X, Y = np.meshgrid(x, y) 
   
Z1 = np.exp(X * Y) 
z = 50 * Z1 
z[:5, :5] = -1
z = ma.masked_where(z <= 0, z) 
   
cs = plt.contourf(X, Y, z, 
                  locator = ticker.LogLocator(), 
                  cmap ="bone") 
  
cbar = plt.colorbar(cs) 
  
plt.title('matplotlib.pyplot.contourf() Example') 
plt.show() 

Output:

Example #2:

# Implementation of matplotlib function 
import matplotlib.pyplot as plt 
import numpy as np 
   
# invent some numbers, turning  
# the x and y arrays into simple 
# 2d arrays, which make combining  
# them together easier. 
x = np.linspace(-3, 15, 50).reshape(1, -1) 
y = np.linspace(-3, 15, 20).reshape(-1, 1) 
z = np.cos(x)*2 - np.sin(y)*2
  
# we no longer need x and y to 
# be 2 dimensional, so flatten them. 
x, y = x.flatten(), y.flatten() 
   
cs = plt.contourf(x, y, z,  
                  hatches =['-', '/', 
                            '\\', '//'], 
                  cmap ='Greens', 
                  extend ='both', 
                  alpha = 1) 
  
plt.colorbar(cs) 
  
plt.title('matplotlib.pyplot.contourf() Example') 
plt.show() 