极速阅览

Hexbin

A hexbin plot is useful to represent the relationship of 2 numerical variables when you have a lot of data points. Without overlapping of the points, the plotting window is split into several hexbins. The color of each hexbin denotes the number of points in it. This can be easily done using the hexbin() function of matplotlib. Note that you can change the size of the bins using the gridsize argument. The parameters of hexbin() function used in the example are:

x, y: The data positions
gridsize: the number of hexagons in the x-direction and the y-direction

Libraries & Dataset

Let's start by import a few libraries and create a dataset:

# libraries import pandas as pd import matplotlib.pyplot as plt import numpy as np # create data df = pd.DataFrame({ 'x': np.random.normal(size=100000), 'y': np.random.normal(size=100000) }) df.head()

x y 0 1 2 3 4

-0.802614	-0.745659
-0.861153	0.013962
-1.847799	1.002161
0.263749	0.264361
2.192508	0.464232

Make the plot

Making an hexbin plot is quite straightforward with the hexbin() function from matplotlib

fig, axs = plt.subplots(ncols=2, figsize=(8,4)) # Make the plot axs[0].hexbin(df['x'], df['y'], gridsize=(15,15)) # We can control the size of the bins: axs[1].hexbin(df['x'], df['y'], gridsize=(150,150)) plt.show()

Color

It is possible to change the color palette applied to the plot with the cmap argument. Read this page to learn more about color palette with matplotlib and pick up the right one.

fig, axs = plt.subplots(ncols=2, nrows=2, figsize=(8,8)) # red colormap axs[0,0].hexbin(df['x'], df['y'], gridsize=(15,15), cmap=plt.cm.Reds_r) axs[0,0].set_title('cmap=plt.cm.Reds') # blue colormap axs[0,1].hexbin(df['x'], df['y'], gridsize=(15,15), cmap=plt.cm.Blues_r) axs[0,1].set_title('cmap=plt.cm.Blues') # green colormap axs[1,0].hexbin(df['x'], df['y'], gridsize=(15,15), cmap=plt.cm.Greens_r) axs[1,0].set_title('cmap=plt.cm.Greens') # grey colormap axs[1,1].hexbin(df['x'], df['y'], gridsize=(15,15), cmap=plt.cm.Greys_r) axs[1,1].set_title('cmap=plt.cm.Greys') plt.show()

Colorbar and legend

Note that you can easily add a color bar beside the plot using colorbar() function.

plt.hexbin(df['x'], df['y'], gridsize=(15,15), cmap=plt.cm.Greys_r) plt.colorbar() plt.show()

Hexbin plot with matplotlib

Hexbin

Libraries & Dataset

Make the plot

Color

Colorbar and legend

Going further

🚨 Grab the Data To Viz poster!

Hexbin plot with matplotlib

Hexbin

Libraries & Dataset

Make the plot

Color

Colorbar and legend

Going further

Correlation

🚨 Grab the Data To Viz poster!