How to create animated scatterplots with seaborn and imageio

In this quick tutorial, I’ll show you how to create an animated scatterplot using the libraries matplotlib or seaborn and imageio. Here’s the GitHub repo of this project.

The scatterplot illustrates the relationship between life expectancy and fertility rate of world’s countries from 1960 to 2015, based on the Gapminder data set:

The animated scatterplot is basically made of several overlapping static plots. Here’s how to create the animation step-by-step:

1. Create static scatterplots for each year in the data set.

The scatterplots depict life_expectancy on the x axis and fertility_rate on the y axis. To make the plots even more insightful, the size of the points illustrates the population number and their color illustrates the continent.

<span>import</span> <span>matplotlib.pyplot</span> <span>as</span> <span>plt</span> 
<span>%</span><span>matplotlib</span> <span>inline</span>
<span>import</span> <span>seaborn</span> <span>as</span> <span>sns</span>
<span>sns</span><span>.</span><span>scatterplot</span><span>(</span><span>x</span><span>=</span><span>'</span><span>life_expectancy</span><span>'</span><span>,</span>
                <span>y</span><span>=</span><span>'</span><span>fertility_rate</span><span>'</span><span>,</span>
                <span>hue</span><span>=</span><span>'</span><span>continent</span><span>'</span><span>,</span>
                <span>size</span><span>=</span><span>'</span><span>population</span><span>'</span><span>,</span>
                <span>sizes</span><span>=</span><span>(</span><span>10</span><span>,</span> <span>1000</span><span>),</span>
                <span>legend</span><span>=</span><span>False</span><span>,</span>
                <span>data</span><span>=</span><span>gapminder_df</span><span>.</span><span>loc</span><span>[</span><span>gapminder_df</span><span>[</span><span>'</span><span>year</span><span>'</span><span>]</span><span>==</span><span>year</span><span>],</span>
                <span>alpha</span><span>=</span><span>0.7</span><span>,</span>
                <span>palette</span><span>=</span><span>'</span><span>Set2</span><span>'</span><span>)</span>
<span>plt</span><span>.</span><span>title</span><span>(</span><span>f</span><span>'</span><span>{</span><span>year</span><span>}</span><span>'</span><span>,</span> <span>loc</span><span>=</span><span>'</span><span>center</span><span>'</span><span>,</span> <span>fontsize</span><span>=</span><span>20</span><span>,</span> <span>color</span><span>=</span><span>'</span><span>black</span><span>'</span><span>,</span> <span>fontweight</span><span>=</span><span>'</span><span>bold</span><span>'</span><span>)</span>
<span>plt</span><span>.</span><span>xlabel</span><span>(</span><span>'</span><span>Life expectancy</span><span>'</span><span>)</span>
<span>plt</span><span>.</span><span>ylabel</span><span>(</span><span>'</span><span>Fertility rate</span><span>'</span><span>)</span>
<span>import</span> <span>matplotlib.pyplot</span> <span>as</span> <span>plt</span> 
<span>%</span><span>matplotlib</span> <span>inline</span>
<span>import</span> <span>seaborn</span> <span>as</span> <span>sns</span>

<span>sns</span><span>.</span><span>scatterplot</span><span>(</span><span>x</span><span>=</span><span>'</span><span>life_expectancy</span><span>'</span><span>,</span>
                <span>y</span><span>=</span><span>'</span><span>fertility_rate</span><span>'</span><span>,</span>
                <span>hue</span><span>=</span><span>'</span><span>continent</span><span>'</span><span>,</span>
                <span>size</span><span>=</span><span>'</span><span>population</span><span>'</span><span>,</span>
                <span>sizes</span><span>=</span><span>(</span><span>10</span><span>,</span> <span>1000</span><span>),</span>
                <span>legend</span><span>=</span><span>False</span><span>,</span>
                <span>data</span><span>=</span><span>gapminder_df</span><span>.</span><span>loc</span><span>[</span><span>gapminder_df</span><span>[</span><span>'</span><span>year</span><span>'</span><span>]</span><span>==</span><span>year</span><span>],</span>
                <span>alpha</span><span>=</span><span>0.7</span><span>,</span>
                <span>palette</span><span>=</span><span>'</span><span>Set2</span><span>'</span><span>)</span>

<span>plt</span><span>.</span><span>title</span><span>(</span><span>f</span><span>'</span><span>{</span><span>year</span><span>}</span><span>'</span><span>,</span> <span>loc</span><span>=</span><span>'</span><span>center</span><span>'</span><span>,</span> <span>fontsize</span><span>=</span><span>20</span><span>,</span> <span>color</span><span>=</span><span>'</span><span>black</span><span>'</span><span>,</span> <span>fontweight</span><span>=</span><span>'</span><span>bold</span><span>'</span><span>)</span>

<span>plt</span><span>.</span><span>xlabel</span><span>(</span><span>'</span><span>Life expectancy</span><span>'</span><span>)</span>
<span>plt</span><span>.</span><span>ylabel</span><span>(</span><span>'</span><span>Fertility rate</span><span>'</span><span>)</span>
import matplotlib.pyplot as plt 
%matplotlib inline
import seaborn as sns

sns.scatterplot(x='life_expectancy',
                y='fertility_rate',
                hue='continent',
                size='population',
                sizes=(10, 1000),
                legend=False,
                data=gapminder_df.loc[gapminder_df['year']==year],
                alpha=0.7,
                palette='Set2')

plt.title(f'{year}', loc='center', fontsize=20, color='black', fontweight='bold')

plt.xlabel('Life expectancy')
plt.ylabel('Fertility rate')

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2. Export the scatterplot images to a designated folder.
You need to save all the individual scatterplots, so that you can overlap the images in the next step.

<span>import</span> <span>imageio</span>
<span>import</span> <span>os</span>
<span>images</span> <span>=</span> <span>[]</span>
<span>folder</span><span>=</span><span>'</span><span>/path/to/folder/images</span><span>'</span>
<span>if</span> <span>not</span> <span>os</span><span>.</span><span>path</span><span>.</span><span>exists</span><span>(</span><span>folder</span><span>):</span>
    <span>os</span><span>.</span><span>mkdir</span><span>(</span><span>folder</span><span>)</span>
<span>import</span> <span>imageio</span>
<span>import</span> <span>os</span>

<span>images</span> <span>=</span> <span>[]</span>
<span>folder</span><span>=</span><span>'</span><span>/path/to/folder/images</span><span>'</span>

<span>if</span> <span>not</span> <span>os</span><span>.</span><span>path</span><span>.</span><span>exists</span><span>(</span><span>folder</span><span>):</span>
    <span>os</span><span>.</span><span>mkdir</span><span>(</span><span>folder</span><span>)</span>
import imageio
import os

images = []
folder='/path/to/folder/images'

if not os.path.exists(folder):
    os.mkdir(folder)

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3. Join the individual images in chronological order.

<span>filename</span> <span>=</span> <span>f</span><span>'</span><span>lifeexp_</span><span>{</span><span>year</span><span>}</span><span>.png</span><span>'</span>
<span>plt</span><span>.</span><span>savefig</span><span>(</span><span>os</span><span>.</span><span>path</span><span>.</span><span>join</span><span>(</span><span>folder</span><span>,</span><span>filename</span><span>))</span>
<span>images</span><span>.</span><span>append</span><span>(</span><span>imageio</span><span>.</span><span>imread</span><span>(</span><span>os</span><span>.</span><span>path</span><span>.</span><span>join</span><span>(</span><span>folder</span><span>,</span><span>filename</span><span>)))</span>
<span>filename</span> <span>=</span> <span>f</span><span>'</span><span>lifeexp_</span><span>{</span><span>year</span><span>}</span><span>.png</span><span>'</span>
<span>plt</span><span>.</span><span>savefig</span><span>(</span><span>os</span><span>.</span><span>path</span><span>.</span><span>join</span><span>(</span><span>folder</span><span>,</span><span>filename</span><span>))</span>
<span>images</span><span>.</span><span>append</span><span>(</span><span>imageio</span><span>.</span><span>imread</span><span>(</span><span>os</span><span>.</span><span>path</span><span>.</span><span>join</span><span>(</span><span>folder</span><span>,</span><span>filename</span><span>)))</span>
filename = f'lifeexp_{year}.png'
plt.savefig(os.path.join(folder,filename))
images.append(imageio.imread(os.path.join(folder,filename)))

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4. Export the scatterplots sequence as a gif.
The fps (frames per second) parameter sets the speed of the animation.

<span>imageio</span><span>.</span><span>mimsave</span><span>(</span><span>os</span><span>.</span><span>path</span><span>.</span><span>join</span><span>(</span><span>folder</span><span>,</span><span>'</span><span>scatterplot.gif</span><span>'</span><span>),</span> <span>images</span><span>,</span> <span>fps</span><span>=</span><span>20</span><span>)</span>
<span>imageio</span><span>.</span><span>mimsave</span><span>(</span><span>os</span><span>.</span><span>path</span><span>.</span><span>join</span><span>(</span><span>folder</span><span>,</span><span>'</span><span>scatterplot.gif</span><span>'</span><span>),</span> <span>images</span><span>,</span> <span>fps</span><span>=</span><span>20</span><span>)</span>
imageio.mimsave(os.path.join(folder,'scatterplot.gif'), images, fps=20)

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Now, putting everything together, here’s the full code and the animated scatterplot:

<span>import</span> <span>pandas</span> <span>as</span> <span>pd</span>
<span>import</span> <span>matplotlib.pyplot</span> <span>as</span> <span>plt</span> 
<span>%</span><span>matplotlib</span> <span>inline</span>
<span>import</span> <span>seaborn</span> <span>as</span> <span>sns</span>
<span>import</span> <span>imageio</span>
<span>import</span> <span>os</span>
<span>images</span> <span>=</span> <span>[]</span>
<span>folder</span><span>=</span><span>'</span><span>/home/lorena/Documents/bootcamp/W1/images</span><span>'</span>
<span>if</span> <span>not</span> <span>os</span><span>.</span><span>path</span><span>.</span><span>exists</span><span>(</span><span>folder</span><span>):</span>
    <span>os</span><span>.</span><span>mkdir</span><span>(</span><span>folder</span><span>)</span>
<span>for</span> <span>year</span> <span>in</span> <span>range</span><span>(</span><span>1960</span><span>,</span> <span>2016</span><span>):</span>
    <span>plt</span><span>.</span><span>axis</span><span>((</span><span>0</span><span>,</span> <span>100</span><span>,</span> <span>0</span><span>,</span> <span>10</span><span>))</span>
    <span>sns</span><span>.</span><span>scatterplot</span><span>(</span><span>x</span><span>=</span><span>'</span><span>life_expectancy</span><span>'</span><span>,</span>
                    <span>y</span><span>=</span><span>'</span><span>fertility_rate</span><span>'</span><span>,</span>
                    <span>hue</span><span>=</span><span>'</span><span>continent</span><span>'</span><span>,</span>
                    <span>size</span><span>=</span><span>'</span><span>population</span><span>'</span><span>,</span>
                    <span>sizes</span><span>=</span><span>(</span><span>10</span><span>,</span> <span>1000</span><span>),</span>
                    <span>legend</span><span>=</span><span>False</span><span>,</span>
                    <span>data</span><span>=</span><span>gapminder_df</span><span>.</span><span>loc</span><span>[</span><span>gapminder_df</span><span>[</span><span>'</span><span>year</span><span>'</span><span>]</span><span>==</span><span>year</span><span>],</span>
                    <span>alpha</span><span>=</span><span>0.7</span><span>,</span>
                    <span>palette</span><span>=</span><span>'</span><span>Set2</span><span>'</span><span>)</span>
    <span>plt</span><span>.</span><span>title</span><span>(</span><span>f</span><span>'</span><span>{</span><span>year</span><span>}</span><span>'</span><span>,</span> <span>loc</span><span>=</span><span>'</span><span>center</span><span>'</span><span>,</span> <span>fontsize</span><span>=</span><span>20</span><span>,</span> <span>color</span><span>=</span><span>'</span><span>black</span><span>'</span><span>,</span> <span>fontweight</span><span>=</span><span>'</span><span>bold</span><span>'</span><span>)</span>
    <span>#plt.title(f'inspired by Hans Rosling', loc='right', fontsize=10, color='grey', style='italic', pad=-20) </span>
    <span>#plt.legend(bbox_to_anchor=(0.74, 0.85), loc='center') </span>
    <span>plt</span><span>.</span><span>xlabel</span><span>(</span><span>'</span><span>Life expectancy</span><span>'</span><span>)</span>
    <span>plt</span><span>.</span><span>ylabel</span><span>(</span><span>'</span><span>Fertility rate</span><span>'</span><span>)</span>
    <span>#plt.annotate({country}, ) </span>
    <span>filename</span> <span>=</span> <span>f</span><span>'</span><span>lifeexp_</span><span>{</span><span>year</span><span>}</span><span>.png</span><span>'</span>
    <span>plt</span><span>.</span><span>savefig</span><span>(</span><span>os</span><span>.</span><span>path</span><span>.</span><span>join</span><span>(</span><span>folder</span><span>,</span><span>filename</span><span>))</span>
    <span>images</span><span>.</span><span>append</span><span>(</span><span>imageio</span><span>.</span><span>imread</span><span>(</span><span>os</span><span>.</span><span>path</span><span>.</span><span>join</span><span>(</span><span>folder</span><span>,</span><span>filename</span><span>)))</span>
    <span>plt</span><span>.</span><span>figure</span><span>()</span>
<span>imageio</span><span>.</span><span>mimsave</span><span>(</span><span>os</span><span>.</span><span>path</span><span>.</span><span>join</span><span>(</span><span>folder</span><span>,</span><span>'</span><span>scatterplot.gif</span><span>'</span><span>),</span> <span>images</span><span>,</span> <span>fps</span><span>=</span><span>20</span><span>)</span>
<span>import</span> <span>pandas</span> <span>as</span> <span>pd</span>
<span>import</span> <span>matplotlib.pyplot</span> <span>as</span> <span>plt</span> 
<span>%</span><span>matplotlib</span> <span>inline</span>
<span>import</span> <span>seaborn</span> <span>as</span> <span>sns</span>
<span>import</span> <span>imageio</span>
<span>import</span> <span>os</span>

<span>images</span> <span>=</span> <span>[]</span>
<span>folder</span><span>=</span><span>'</span><span>/home/lorena/Documents/bootcamp/W1/images</span><span>'</span>

<span>if</span> <span>not</span> <span>os</span><span>.</span><span>path</span><span>.</span><span>exists</span><span>(</span><span>folder</span><span>):</span>
    <span>os</span><span>.</span><span>mkdir</span><span>(</span><span>folder</span><span>)</span>

<span>for</span> <span>year</span> <span>in</span> <span>range</span><span>(</span><span>1960</span><span>,</span> <span>2016</span><span>):</span>

    <span>plt</span><span>.</span><span>axis</span><span>((</span><span>0</span><span>,</span> <span>100</span><span>,</span> <span>0</span><span>,</span> <span>10</span><span>))</span>

    <span>sns</span><span>.</span><span>scatterplot</span><span>(</span><span>x</span><span>=</span><span>'</span><span>life_expectancy</span><span>'</span><span>,</span>
                    <span>y</span><span>=</span><span>'</span><span>fertility_rate</span><span>'</span><span>,</span>
                    <span>hue</span><span>=</span><span>'</span><span>continent</span><span>'</span><span>,</span>
                    <span>size</span><span>=</span><span>'</span><span>population</span><span>'</span><span>,</span>
                    <span>sizes</span><span>=</span><span>(</span><span>10</span><span>,</span> <span>1000</span><span>),</span>
                    <span>legend</span><span>=</span><span>False</span><span>,</span>
                    <span>data</span><span>=</span><span>gapminder_df</span><span>.</span><span>loc</span><span>[</span><span>gapminder_df</span><span>[</span><span>'</span><span>year</span><span>'</span><span>]</span><span>==</span><span>year</span><span>],</span>
                    <span>alpha</span><span>=</span><span>0.7</span><span>,</span>
                    <span>palette</span><span>=</span><span>'</span><span>Set2</span><span>'</span><span>)</span>

    <span>plt</span><span>.</span><span>title</span><span>(</span><span>f</span><span>'</span><span>{</span><span>year</span><span>}</span><span>'</span><span>,</span> <span>loc</span><span>=</span><span>'</span><span>center</span><span>'</span><span>,</span> <span>fontsize</span><span>=</span><span>20</span><span>,</span> <span>color</span><span>=</span><span>'</span><span>black</span><span>'</span><span>,</span> <span>fontweight</span><span>=</span><span>'</span><span>bold</span><span>'</span><span>)</span>
    <span>#plt.title(f'inspired by Hans Rosling', loc='right', fontsize=10, color='grey', style='italic', pad=-20) </span>
    <span>#plt.legend(bbox_to_anchor=(0.74, 0.85), loc='center') </span>
    <span>plt</span><span>.</span><span>xlabel</span><span>(</span><span>'</span><span>Life expectancy</span><span>'</span><span>)</span>
    <span>plt</span><span>.</span><span>ylabel</span><span>(</span><span>'</span><span>Fertility rate</span><span>'</span><span>)</span>
    <span>#plt.annotate({country}, ) </span>
    <span>filename</span> <span>=</span> <span>f</span><span>'</span><span>lifeexp_</span><span>{</span><span>year</span><span>}</span><span>.png</span><span>'</span>

    <span>plt</span><span>.</span><span>savefig</span><span>(</span><span>os</span><span>.</span><span>path</span><span>.</span><span>join</span><span>(</span><span>folder</span><span>,</span><span>filename</span><span>))</span>

    <span>images</span><span>.</span><span>append</span><span>(</span><span>imageio</span><span>.</span><span>imread</span><span>(</span><span>os</span><span>.</span><span>path</span><span>.</span><span>join</span><span>(</span><span>folder</span><span>,</span><span>filename</span><span>)))</span>

    <span>plt</span><span>.</span><span>figure</span><span>()</span>

<span>imageio</span><span>.</span><span>mimsave</span><span>(</span><span>os</span><span>.</span><span>path</span><span>.</span><span>join</span><span>(</span><span>folder</span><span>,</span><span>'</span><span>scatterplot.gif</span><span>'</span><span>),</span> <span>images</span><span>,</span> <span>fps</span><span>=</span><span>20</span><span>)</span>
import pandas as pd
import matplotlib.pyplot as plt 
%matplotlib inline
import seaborn as sns
import imageio
import os

images = []
folder='/home/lorena/Documents/bootcamp/W1/images'

if not os.path.exists(folder):
    os.mkdir(folder)

for year in range(1960, 2016):

    plt.axis((0, 100, 0, 10))

    sns.scatterplot(x='life_expectancy',
                    y='fertility_rate',
                    hue='continent',
                    size='population',
                    sizes=(10, 1000),
                    legend=False,
                    data=gapminder_df.loc[gapminder_df['year']==year],
                    alpha=0.7,
                    palette='Set2')

    plt.title(f'{year}', loc='center', fontsize=20, color='black', fontweight='bold')
    #plt.title(f'inspired by Hans Rosling', loc='right', fontsize=10, color='grey', style='italic', pad=-20) 
    #plt.legend(bbox_to_anchor=(0.74, 0.85), loc='center') 
    plt.xlabel('Life expectancy')
    plt.ylabel('Fertility rate')
    #plt.annotate({country}, ) 
    filename = f'lifeexp_{year}.png'

    plt.savefig(os.path.join(folder,filename))

    images.append(imageio.imread(os.path.join(folder,filename)))

    plt.figure()

imageio.mimsave(os.path.join(folder,'scatterplot.gif'), images, fps=20)

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原文链接：How to create animated scatterplots with seaborn and imageio