5 Best Ways to Display a Hexbin Plot in Python Using Seaborn Library

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πŸ’‘ Problem Formulation: When dealing with large datasets containing bivariate data, scatter plots can become cluttered and less informative. A hexbin plot merges points into hexagonal bins, providing a clear visualization of the density distribution. This article provides five methods to use the Seaborn library for creating informative hexbin plots in Python, assuming you have a set of x and y data points for which you want to visualize the density distribution.

Method 1: Basic Hexbin Plot

This method covers how to create a basic hexbin plot in Seaborn to visualize the density of points. The seaborn.jointplot() function is used with the kind='hex' parameter to generate the plot.

Here’s an example:

import seaborn as sns
import matplotlib.pyplot as plt

# Sample data
x, y = sns.load_dataset('diamonds')[['carat', 'price']].T

# Create a basic hexbin plot
sns.jointplot(x=x, y=y, kind='hex')
plt.show()

The output is a hexbin plot displaying the density of points where ‘x’ and ‘y’ values intersect on a 2D plane.

This snippet loads a sample dataset of diamonds, selects carat and price for the ‘x’ and ‘y’ data, respectively, and then uses seaborn.jointplot() with the kind parameter set to 'hex' to create and display the hexbin plot.

Method 2: Custom Bin Size

Adjusting the size of hexbins can provide a different perspective on data density. The gridsize parameter within the seaborn.jointplot() function allows customization of hexbin sizes.

Here’s an example:

# Using previously loaded data from Method 1

# Create a hexbin plot with custom bin size
sns.jointplot(x=x, y=y, kind='hex', gridsize=30)
plt.show()

The resulting plot has hexagons that are larger or smaller depending on the specified gridsize, affecting the granularity of the data visualization.

This code modifies the hexbin size by setting the gridsize parameter. A gridsize of 30 is used in this example, which increases or decreases the size of the hexagons depending on the chosen value, consequently changing how data density is visualized.

Method 3: Adding Color Maps

Color maps can enhance the visualization of density differences in a hexbin plot. Seaborn provides a cmap parameter that applies a matplotlib colormap to the hexbin plot.

Here’s an example:

# Using previously loaded data from Method 1

# Create a hexbin plot with a color map
sns.jointplot(x=x, y=y, kind='hex', cmap='viridis')
plt.show()

The output is a hexbin plot with varying colors representing different densities of points.

By specifying a cmap such as ‘viridis’, the plot’s hexbins are color-coded to reflect the density of points, with darker shades typically representing higher concentrations.

Method 4: Overlaying with a Scatter Plot

For additional context, a scatter plot can be overlaid on a hexbin plot. This is achieved by using the plot_joint method from the JointGrid object that seaborn.jointplot() returns.

Here’s an example:

# Using previously loaded data from Method 1

# Create a hexbin plot with scatter plot overlay
joint_plot = sns.jointplot(x=x, y=y, kind='hex')
joint_plot.plot_joint(plt.scatter, color='white', s=5, edgecolor='blue')
plt.show()

The output is a hexbin plot with a superimposed scatter plot, providing an additional layer of information about individual data points.

Through the plot_joint method, additional plotting functions such as plt.scatter can be called to overlay the scatter plot onto the hexbin plot, enhancing the representation of data distribution and individual data points.

Bonus One-Liner Method 5: Hexbin Plot with DataFrames

The seaborn library can integrate seamlessly with Pandas DataFrames, enabling a hexbin plot to be created with just a single line of code using DataFrame columns.

Here’s an example:

import pandas as pd

# Assuming 'df' is a Pandas DataFrame with 'carat' and 'price' columns

# One-liner to create hexbin plot
sns.jointplot(data=df, x='carat', y='price', kind='hex')

The output is a hexbin plot based on the DataFrame’s ‘carat’ and ‘price’ columns.

This one-liner takes advantage of Seaborn’s integration with Pandas, plotting directly from DataFrame column names specified in the x and y parameters alongside the dataset itself as the data parameter.

Summary/Discussion

  • Method 1: Basic Hexbin Plot. Offers a straightforward visualization of data density. Lacks customization.
  • Method 2: Custom Bin Size. Provides control over granularity. May require tweaking for optimal size.
  • Method 3: Adding Color Maps. Enhances plot interpretation through visual cues. Choice of colormap is crucial.
  • Method 4: Overlaying with a Scatter Plot. Adds depth to the visualization. Can become cluttered if not used judiciously.
  • Method 5: Hexbin Plot with DataFrames. Quick and convenient for DataFrame users. Limited to DataFrame context.