Matplotlib.pyplot.tricontourf() in Python

03 Jun, 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.  
The tricontourf() function in pyplot module of matplotlib library is used to draw contours on an unstructured triangular grid. 
Syntax:  matplotlib.pyplot.tricontourf(\*args, \*\*kwargs)
Parameters: This method accept the following parameters that are described below:  
x, y: These parameter are the x and y coordinates of the data which is to be plot.
triangulation: This parameter is a matplotlib.tri.Triangulation object.
Z: This parameter is is the array of values to contour, one per point in the triangulation.
**kwargs: This parameter is Text properties that is used to control the appearance of the labels.
All remaining args and kwargs are the same as for matplotlib.pyplot.plot().
Returns: This returns the list of 2 Line2D containing following:  
The lines plotted for triangles edges.
The markers plotted for triangles nodes
Note: tricontourf-only keyword arguments is antialiased which is a bool enable antialiasing which used in contours on an unstructured triangular grid.
Below examples illustrate the matplotlib.pyplot.tricontourf() function in matplotlib.pyplot:Example 1:  
Python3
#Implementation of matplotlib functionimport matplotlib.pyplot as plt import matplotlib.tri as mtri import numpy as np             # Create triangulation. x = np.asarray([0, 1, 0, 3, 0.5, 1.5,                2.5, 1, 2, 1.5]) y = np.asarray([0, 0, 0, 0, 1.0, 1.0,                 1.0, 2, 2, 3.0])   triangles = [[0, 1, 4], [1, 5, 4], [2, 6, 5],              [4, 5, 7], [5, 6, 8], [5, 8, 7],              [7, 8, 9], [1, 2, 5], [2, 3, 6]]     triang = mtri.Triangulation(x, y, triangles) z = np.cos(2.5 * x*x) + np.sin(2.5 * x*x)   t = plt.tricontourf(triang, z)  plt.title('matplotlib.pyplot.tricontourf() Example\n',          fontsize=14, fontweight='bold')  plt.show()
Output:  
Example 2:  
Python3
#Implementation of matplotlib functionimport matplotlib.pyplot as plt import matplotlib.tri as tri import numpy as np         n_angles = 60n_radii = 10min_radius = 0.35radii = np.linspace(min_radius, 0.95, n_radii)     angles = np.linspace(0, np.pi, n_angles, endpoint = False) angles = np.repeat(angles[..., np.newaxis], n_radii, axis = 1) angles[:, 1::2] += np.pi / n_angles     x = (10 * radii * np.cos(angles)).flatten() y = (10 * radii * np.sin(angles)).flatten() z = (np.cos(4*(radii)**2) * np.sin((angles)**2)).flatten()     triang = tri.Triangulation(x, y)     triang.set_mask(np.hypot(x[triang.triangles].mean(axis = 1),                          y[triang.triangles].mean(axis = 1))                 < min_radius)   tcf = plt.tricontourf(triang, z)  plt.colorbar(tcf) plt.title('matplotlib.pyplot.tricontourf() Example\n',          fontsize=14, fontweight='bold')  plt.show()
Output: 
 
Matplotlib Pyplot-class
Python-matplotlib
Python
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