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:
# Implementation of matplotlib function import numpy as np import matplotlib.pyplot as plt import matplotlib.ticker as ticker import matplotlib delta = 0.15x = 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() |
Output:
Example #2:
# Implementation of matplotlib function import matplotlib import numpy as np import matplotlib.cm as cm import matplotlib.pyplot as plt delta = 0.25x = 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() |
Output:
