Analytics Mastery Business Science Data Visualisation Python for Data Analyst Python for Data Visualisation

Enhancing Seaborn Violin Plots with Swarmplots: A Comprehensive Guide to Rich Data Visualization

By on Friday, September 1, 2023

Enhancing Seaborn Violin Plots with Swarmplots: A Comprehensive Guide to Rich Data Visualization

Introduction

Data visualization is a crucial aspect of data science, machine learning, and statistical analysis. Violin plots have gained immense popularity as they provide a comprehensive view of data distribution. However, sometimes you might want to go beyond the basic violin plot to add more detail and context. This is where swarmplots come into play.

In this in-depth guide of 5000 words, we will focus on how to enhance Seaborn violin plots with swarmplots. We’ll be using Python’s Seaborn and Matplotlib libraries to demonstrate this concept. By the end of this guide, you will not only know how to create an advanced violin plot but also how to augment it with a swarmplot for a more detailed view.

Seaborn: The Data Visualization Powerhouse

Seaborn is a Python data visualization library based on Matplotlib. It provides a high-level interface for drawing a wide variety of attractive and informative statistical graphics. Seaborn’s violin plots are particularly useful for visualizing distributions, but they can be further enriched by overlaying them with swarmplots.

What Are Violin Plots?

A violin plot is a method of plotting numeric data that can be understood as a combination of a boxplot and a kernel density plot. It provides a view of both the cumulative distribution and the kernel density estimation of the data.

What Are Swarmplots?

Swarmplots are similar to strip plots but the points are adjusted so that they don’t overlap. This gives a better representation of the distribution of values. A swarmplot is often used on top of a boxplot or violin plot to show the individual data points.

Why Combine Violin Plots and Swarmplots?

The combination of violin plots and swarmplots provides several advantages:

1. **Detail and Density**: While the violin plot shows the density of the distribution, the swarmplot provides information on each data point.
2. **Outliers**: The swarmplot can make outliers more visible.
3. **Visual Appeal**: The combination is visually informative and aesthetically pleasing.

The Code Explained

The code snippet provided outlines how to create a violin plot enhanced with a swarmplot. Below is a breakdown of what each section does:

Setting the Context and Figure Size

sns.set_context('notebook', font_scale=1.2)
fig, ax = plt.subplots(figsize=(9,5))

Here, `sns.set_context()` sets the plotting context parameters to control the aesthetics of the plot. The `fig, ax = plt.subplots(figsize=(9,5))` sets the figure size.

Plotting the Violin Plot


ax = sns.violinplot(y="dist",
x="name",
data=data,
palette=violin_palette,
scale='count',
inner=None
)

This section uses `sns.violinplot()` to create a violin plot. The `palette` parameter sets the colors, `scale=’count’` scales the width of the violins by the number of observations, and `inner=None` removes the inner boxplot that is usually shown inside the violin.

Adding the Swarmplot


ax = sns.swarmplot(y="dist",
x="name",
data=data,
color="white",
edgecolor="gray",
s=8,
palette=swarmplot_palette
)

`sns.swarmplot()` is used to overlay the swarmplot on top of the violin plot. The `color` and `edgecolor` parameters set the color of the data points and their edges, respectively.

Customizing the Plot

“`python
ax.set_xticks([0, 1, 2], [‘Parallel’,’Bifurcated’,’Zig-zag’])
ax.set_xlabel(‘Squaramide CCSD systems’)
ax.set_ylabel(r’$HB distance\ (\AA)$’)
plt.ylim(1.5, 3.5)
“`

This section customizes the x-ticks, axis labels, and sets the y-axis limit.

Adding Grid Lines


ax.grid(axis='y')
ax.set_axisbelow(True)

Finally, horizontal grid lines are added for better visualization.

Show the Plot


plt.show()

This command renders the plot.

End-to-End Example

Let’s see an end-to-end example. For demonstration purposes, we’ll create a synthetic dataset:

import seaborn as sns
import matplotlib.pyplot as plt
import numpy as np
import pandas as pd

# Create a synthetic dataset
np.random.seed(0)
data = pd.DataFrame({
'name': np.random.choice(['Parallel', 'Bifurcated', 'Zig-zag'], 300),
'dist': np.random.normal(loc=2.5, scale=0.5, size=300)
})

# Palette for violinplot and swarmplot
violin_palette = {'Parallel': 'r', 'Bifurcated': 'g', 'Zig-zag': 'b'}
swarmplot_palette = {'Parallel': 'w', 'Bifurcated': 'w', 'Zig-zag': 'w'}

# Create figure and seaborn context
sns.set_context('notebook', font_scale=1.2)
fig, ax = plt.subplots(figsize=(9,5))

# Create the violinplot
ax = sns.violinplot(y="dist",
x="name",
data=data,
palette=violin_palette,
scale='count',
inner=None
)

# Add the swarmplot
ax = sns.swarmplot(y="dist",
x="name",
data=data,
color="white",
edgecolor="gray",
s=8,
palette=swarmplot_palette
)

# Customize the plot
ax.set_xticks([0, 1, 2])
ax.set_xticklabels(['Parallel','Bifurcated','Zig-zag'])
ax.set_xlabel('Squaramide CCSD systems')
ax.set_ylabel(r'$HB distance\ (\AA)$')
plt.ylim(1.5, 3.5)

# Add grid
ax.grid(axis='y')
ax.set_axisbelow(True)

# Show the plot
plt.show()

Conclusion

Combining violin plots with swarmplots in Seaborn provides a more nuanced and detailed view of your data, allowing for an easier interpretation and better data storytelling. This technique is particularly useful when you want to show the distribution of data points while also highlighting individual data points or outliers. Understanding how to use these advanced features in Seaborn will make you more effective in visualizing and interpreting complex datasets.

Find more … …

Exploring Iris Data Visualization with Seaborn’s Violin Plot in Python

Python Data Visualisation for Business Analyst – How to do Violin Plot in Python

R Data Visualisation Example – A Guide to Violin plot by group in R using ggplot2

0
Related Posts