Matplotlib.axes.Axes.triplot() in Python

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Matplotlib is a library in Python and it is numerical – mathematical extension for NumPy library. The Axes Class contains most of the figure elements: Axis, Tick, Line2D, Text, Polygon, etc., and sets the coordinate system. And the instances of Axes supports callbacks through a callbacks attribute.

matplotlib.axes.Axes.triplot() Function

The Axes.triplot() function in axes module of matplotlib library is also used to create a unstructured triangular grid as lines and/or markers.

Syntax:
Axes.triplot(ax, *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.

**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

Below examples illustrate the matplotlib.axes.Axes.triplot() function in matplotlib.axes:

Example-1:

# Implementation of matplotlib function 
import matplotlib.pyplot as plt 
import matplotlib.tri as mtri 
import numpy as np 
    
# Create triangulation. 
x = np.asarray([0, 1, 2, 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(1.5 * x) * np.cos(1.5 * y) 
    
fig, axs = plt.subplots() 
axs.tricontourf(triang, z) 
axs.triplot(triang, 'go-', color ='white') 
fig.tight_layout() 
    
axs.set_title('matplotlib.axes.Axes.triplot() Example') 
plt.show() 

Output:

Example-2:

# Implementation of matplotlib function 
import matplotlib.pyplot as plt 
import matplotlib.tri as tri 
import numpy as np 
   
n_angles = 24
n_radii = 9
min_radius = 0.5
radii = np.linspace(min_radius, 0.9, 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 = (radii * np.cos(angles)).flatten() 
y = (radii * np.sin(angles)).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) 
   
fig1, ax1 = plt.subplots() 
ax1.set_aspect('equal') 
ax1.triplot(triang, 'go-', lw = 2) 
ax1.set_title('matplotlib.axes.Axes.triplot() Example') 
plt.show() 