Creating a Color Demo Chart

Introduction

In this lab, we will learn how to create a color demo chart using Python's Matplotlib library. Matplotlib provides a variety of ways to specify colors, which can be used in charts, graphs, and other visualizations. We will explore these different ways of specifying colors and use them to create a chart showing voltage vs. time.

VM Tips

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Skills Graph

Import Required Libraries

Before we begin, we need to import the Matplotlib and NumPy libraries:

import matplotlib.pyplot as plt
import numpy as np

Define Data

Next, we need to define the data that we will use for our chart. We will create a sine wave with 201 data points:

t = np.linspace(0.0, 2.0, 201)
s = np.sin(2 * np.pi * t)

Specify Colors

Matplotlib provides several ways to specify colors, including:

1. An RGB or RGBA tuple of float values in [0, 1].
2. A hex RGB or RGBA string.
3. A shorthand hex RGB or RGBA string.
4. A string representation of a float value in [0, 1] inclusive for gray level.
5. A single letter string, i.e. one of {'b', 'g', 'r', 'c', 'm', 'y', 'k', 'w'}.
6. A X11/CSS4 ("html") color name.
7. A name from the xkcd color survey, prefixed with 'xkcd:'.
8. A "Cn" color spec, i.e. 'C' followed by a number.
9. One of {'tab:blue', 'tab:orange', 'tab:green', 'tab:red', 'tab:purple', 'tab:brown', 'tab:pink', 'tab:gray', 'tab:olive', 'tab:cyan'}.

We will use several of these methods to specify the colors for our chart.

Create Chart

Now we can create our chart using the data and colors that we have specified:

fig, ax = plt.subplots(facecolor=(.18, .31, .31))
ax.set_facecolor('#eafff5')
ax.set_title('Voltage vs. time chart', color='0.7')
ax.set_xlabel('Time [s]', color='c')
ax.set_ylabel('Voltage [mV]', color='peachpuff')
ax.plot(t, s, 'xkcd:crimson')
ax.plot(t, .7*s, color='C4', linestyle='--')
ax.tick_params(labelcolor='tab:orange')

Display Chart

Finally, we can display our chart using the following command:

plt.show()

Summary

In this lab, we learned how to create a color demo chart using Python's Matplotlib library. We explored several ways to specify colors and used them to create a chart showing voltage vs. time. We hope that this tutorial has been helpful in learning how to use Matplotlib to create charts and visualizations.