Three Dimensional Plots

While matplotlib is primarily a 2D plotting package, it does have basic 3D plotting capabilities. To create a 3D plot, we need to import Axes3D from mpl_toolkits.mplot3d and then set the keyword projection to '3d' in a subplot call as follows:

import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D

fig = plt.figure()
ax = plt.axes(projection='3d')

# Data for a three-dimensional line

zline = np.linspace(0, 15, 1000)
xline = np.sin(zline)
yline = np.cos(zline)
ax.plot3D(xline, yline, zline, 'red')

Three-dimensional Contour Plots

Analogous to the contour plots we explored in Density and Contour Plots, mplot3d contains tools to create three-dimensional relief plots using the same inputs. Like two-dimensional ax.contour plots, ax.contour3D requires all the input data to be in the form of two-dimensional regular grids, with the Z data evaluated at each point. Here we'll show a three-dimensional contour diagram of a three-dimensional sinusoidal function:

def f(x, y):

    return np.sin(np.sqrt(x ** 2 + y ** 2))

x = np.linspace(-6, 6, 30)

y = np.linspace(-6, 6, 30)

X, Y = np.meshgrid(x, y)

Z = f(X, Y)

fig = plt.figure()

ax = plt.axes(projection='3d')

ax.contour3D(X, Y, Z, 50, cmap='binary')

ax.set_xlabel('x')

ax.set_ylabel('y')

ax.set_zlabel('z')

Wireframes and Surface Plots

Two other types of three-dimensional plots that work on gridded data are wireframes and surface plots. These take a grid of values and project it onto the specified three-dimensional surface, and can make the resulting three-dimensional forms quite easy to visualize. Here's an example of using a wireframe:

fig = plt.figure()

ax = plt.axes(projection='3d')

ax.plot_wireframe(X, Y, Z, color='black')

ax.set_title('wireframe');

A surface plot is like a wireframe plot, but each face of the wireframe is a filled polygon. Adding a colormap to the filled polygons can aid perception of the topology of the surface being visualized:

ax = plt.axes(projection='3d')

ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap='viridis', edgecolor='none')

ax.set_title('surface');