Book Image

NumPy: Beginner's Guide

By : Ivan Idris
Book Image

NumPy: Beginner's Guide

By: Ivan Idris

Overview of this book

Table of Contents (21 chapters)
NumPy Beginner's Guide Third Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
NumPy Functions' References
Index

Time for action – plotting in three dimensions


We will plot a simple three-dimensional function:

  1. Use the 3D keyword to specify a three-dimensional projection for the plot:

    ax = fig.add_subplot(111, projection='3d')
  2. To create a square two-dimensional grid, use the meshgrid() function to initialize the x and y values:

    u = np.linspace(-1, 1, 100)
    
    x, y = np.meshgrid(u, u)
  3. We will specify the row strides, column strides, and the color map for the surface plot. The strides determine the size of the tiles in the surface. The choice for color map is a matter of taste:

    ax.plot_surface(x, y, z,  rstride=4, cstride=4, cmap=cm.YlGnBu_r)

    The result is the following three-dimensional plot:

What just happened?

We created a plot of a three-dimensional function (see three_d.py):

from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt
import numpy as np
from matplotlib import cm

fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')

u = np.linspace(-1, 1, 100)

x, y = np.meshgrid(u, u)
z...