Create Spiral Plot with Python and Matplotlib

Introduction

In this lab, we will use Python and Matplotlib to create a fill spiral plot. We will use the numpy and matplotlib.pyplot libraries to generate the plot.

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Skills Graph

Import libraries

We will import the necessary libraries to generate the plot. We will use numpy for numerical calculations and matplotlib.pyplot for creating the plot.

import matplotlib.pyplot as plt
import numpy as np

Define variables

We will define the variables theta, a, and b for our plot.

theta = np.arange(0, 8*np.pi, 0.1)
a = 1
b = .2

Generate the plot

We will generate the plot by looping through four values of dt and concatenating the resulting x and y arrays.

for dt in np.arange(0, 2*np.pi, np.pi/2.0):

    x = a*np.cos(theta + dt)*np.exp(b*theta)
    y = a*np.sin(theta + dt)*np.exp(b*theta)

    dt = dt + np.pi/4.0

    x2 = a*np.cos(theta + dt)*np.exp(b*theta)
    y2 = a*np.sin(theta + dt)*np.exp(b*theta)

    xf = np.concatenate((x, x2[::-1]))
    yf = np.concatenate((y, y2[::-1]))

    p1 = plt.fill(xf, yf)

plt.show()

Interpretation

The plot generated by the code shows a spiral that is filled with color. The a and b variables control the shape of the spiral, while the theta variable controls the number of revolutions. The loop through dt allows us to create a spiral with four "arms" by rotating the plot by 45 degrees each time.

Summary

In this lab, we learned how to use Python and Matplotlib to generate a fill spiral plot. We defined variables for the plot, generated the plot using a loop, and interpreted the resulting plot. With this knowledge, we can create similar plots with different shapes and colors.