Matplotlib.pyplot.contour() 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.contour() Function
The contour() function in pyplot module of matplotlib library is used to plot contours.
Syntax: matplotlib.pyplot.contour(\*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.contour() function in matplotlib.pyplot:
Example #1:
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.ticker as ticker
import matplotlib
delta = 0.15
x = np.arange( 1.5 , 2.5 , delta)
y = np.arange( 1.0 , 3.0 , delta)
X, Y = np.meshgrid(x, y)
Z = (np.exp(X - Y))
CS1 = plt.contour(X, Y, Z)
fmt = {}
strs = [ '1' , '2' , '3' , '4' , '5' , '6' , '7' ]
for l, s in zip (CS1.levels, strs):
fmt[l] = s
plt.clabel(CS1, CS1.levels, inline = True ,
fmt = fmt, fontsize = 10 )
plt.title( 'matplotlib.pyplot.contour() Example' )
plt.show()
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Output:
Example #2:
import matplotlib
import numpy as np
import matplotlib.cm as cm
import matplotlib.pyplot as plt
delta = 0.25
x = np.arange( - 3.0 , 5.0 , delta)
y = np.arange( - 1.3 , 2.5 , delta)
X, Y = np.meshgrid(x, y)
Z = (np.exp( - X * * 2 - Y * * 2 ) - np.exp( - (X - 1 ) * * 2 - (Y - 1 ) * * 2 ))
fig, ax = plt.subplots()
im = ax.imshow(Z, interpolation = 'bilinear' ,
origin = 'lower' ,
cmap = "bone" ,
extent = ( - 3 , 3 , - 2 , 2 ))
levels = np.arange( - 1.2 , 1.6 , 0.2 )
CS = ax.contour(Z, levels,
origin = 'lower' ,
cmap = 'Greens' ,
linewidths = 2 ,
extent = ( - 3 , 3 , - 2 , 2 ))
zc = CS.collections[ 6 ]
plt.setp(zc, linewidth = 2 )
ax.clabel(CS, levels,
inline = 1 ,
fmt = '% 1.1f' ,
fontsize = 14 )
plt.title( 'matplotlib.pyplot.contour() Example' )
plt.show()
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Output:
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