Control the color in stacked area chart

Once you understand how to create a stacked area chart and which baseline option to choose, it’s highly recommended to custom the colors of your chart. This post explains how to customize colors.

Libraries & Data

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

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

df = pd.DataFrame(
    {
        "x": range(1, 6),
        "y1": [10, 4, 6, 5, 3],
        "y2": [12, 2, 7, 10, 1],
        "y3": [8, 18, 5, 7, 6],
    }
)
df.head()

	x	y1	y2	y3
0	1	10	12	8
1	2	4	2	18
2	3	6	7	5
3	4	5	10	7
4	5	3	1	6

Basic color customization

The easiest way to customize the colors of your chart is to pass to the colors argument a list of colors:

fig, ax = plt.subplots(figsize=(10, 10), dpi=300)

ax.stackplot(
    df["x"],
    df["y1"],
    df["y2"],
    df["y3"],
    colors=["#00496FFF", "#0F85A0FF", "#EDD746FF"],
)

plt.show()

Linewidth style

The edgecolor argument sets the color of the area borders, while linewidth determines how thick those borders are.

fig, ax = plt.subplots(figsize=(10, 10), dpi=300)

ax.stackplot(
    df["x"],
    df["y1"],
    df["y2"],
    df["y3"],
    edgecolor="black",
    linewidth=3,
    colors=["#00496FFF", "#0F85A0FF", "#EDD746FF"],
)

plt.show()

Opacity

We can easily change the opacity of the chart thanks to the alpha argument. Possible values range from 0 (completely transparent) to 1 (completely opaque), and the default one is 1:

fig, ax = plt.subplots(figsize=(10, 10), dpi=300)

ax.stackplot(
    df["x"],
    df["y1"],
    df["y2"],
    df["y3"],
    edgecolor="black",
    linewidth=3,
    alpha=0.6,
    colors=["#00496FFF", "#0F85A0FF", "#EDD746FF"],
)

plt.show()

Pattern inside the areas

fig, ax = plt.subplots(figsize=(10, 10), dpi=300)

ax.stackplot(
    df["x"],
    df["y1"],
    df["y2"],
    df["y3"],
    edgecolor="black",
    linewidth=3,
    colors=["#00496FFF", "#0F85A0FF", "#EDD746FF"],
    hatch=["*", ".", "+"],
)

plt.show()

More colors with PyPalettes

Thanks to the pypalettes library, it's super easy to use a large number of palette in your seaborn/matplotlib charts. You can find your dream palette in the color palette finder, and use the load_cmap() function with the name of the palette you want and then access the colors attribute. Here is an example with the Acadia palette:

from pypalettes import load_cmap

colors = load_cmap("Acadia").colors

fig, ax = plt.subplots(figsize=(10, 10), dpi=300)

ax.stackplot(
    df["x"], df["y1"], df["y2"], df["y3"], edgecolor="black", linewidth=2, colors=colors
)

plt.show()

Going further

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