5. 3D Plotting¶

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Matplotlib Tutorial: 5. 3D plotting

The 3D plotting toolkit introduced in matplotlib version 1.0 can lead to some very nice plots. We'll explore a few of the options here: for more examples, the matplotlib tutorial is a great resource.

Again we'll use inline plotting, though it can be useful to skip the "inline" backend to allow interactive manipulation of the plots.

In [1]:

%pylab inline

Welcome to pylab, a matplotlib-based Python environment [backend: module://IPython.zmq.pylab.backend_inline].
For more information, type 'help(pylab)'.

In [2]:

# This is the 3D plotting toolkit
from mpl_toolkits.mplot3d import Axes3D

Just as before when we created a 2D axes and called several plotting methods on it, here we'll create some 3D axes objects and call 3D plotting routines. Below are several examples.

3D scatter Plot

The 3D scatter plot takes all the same keyword parameters as the 2D scatter plot, so its use should be familiar. To create a 3D axes, we need to pass the argument projection='3d'.

In [3]:

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

z = np.linspace(0, 1, 100)
x = z * np.sin(20 * z)
y = z * np.cos(20 * z)

c = x + y

ax.scatter(x, y, z, c=c)

Out [3]:

<mpl_toolkits.mplot3d.art3d.Patch3DCollection at 0x9bce74c>

3D Line Plot

Like the 2D and 3D scatter command, the 2D and 3D plot command have the same argument structure. Thus plotting a 3D line plot is straightforward:

In [4]:

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

ax.plot(x, y, z, '-b')

Out [4]:

[<mpl_toolkits.mplot3d.art3d.Line3D at 0x9b7daac>]

Surface Plot

Surface plots are connected plots of x, y, and z coordinates. They can be used to make some pretty interesting shapes:

In [5]:

x = np.outer(np.linspace(-2, 2, 30), np.ones(30))
y = x.copy().T
z = np.cos(x ** 2 + y ** 2)

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

ax.plot_surface(x, y, z, cmap=plt.cm.jet, rstride=1, cstride=1, linewidth=0)

Out [5]:

<mpl_toolkits.mplot3d.art3d.Poly3DCollection at 0x9f4570c>

Wire-frame plot

Wire-frame plots draw lines between nearby points. They can be displayed using the plot_wireframe method. Here we'll plot a parametrized sphere:

In [6]:

u = np.linspace(0, np.pi, 30)
v = np.linspace(0, 2 * np.pi, 30)

x = np.outer(np.sin(u), np.sin(v))
y = np.outer(np.sin(u), np.cos(v))
z = np.outer(np.cos(u), np.ones_like(v))


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

ax.plot_wireframe(x, y, z)

Out [6]:

<mpl_toolkits.mplot3d.art3d.Line3DCollection at 0x9f2162c>

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