Filled Area Plots - Plotly Py

This example shows how to fill the area enclosed by traces.

Filled area plot with plotly.express

Plotly Express is the easy-to-use, high-level interface to Plotly, which operates on a variety of types of data and produces easy-to-style figures.

px.area creates a stacked area plot. Each filled area corresponds to one value of the column given by the line_group parameter.

python

import plotly.express as px
df = px.data.gapminder()
fig = px.area(df, x="year", y="pop", color="continent", line_group="country")
fig.show()

Filled area plot in Dash

Dash is the best way to build analytical apps in Python using Plotly figures. To run the app below, run pip install dash, click "Download" to get the code and run python app.py.

Get started with the official Dash docs and learn how to effortlessly style & publish apps like this with <a class="plotly-red" href="https://plotly.com/dash/">Dash Enterprise</a> or <a class="plotly-red" href="https://plotly.com/cloud/">Plotly Cloud</a>.

python

from IPython.display import IFrame
snippet_url = 'https://python-docs-dash-snippets.herokuapp.com/python-docs-dash-snippets/'
IFrame(snippet_url + 'filled-area-plots', width='100%', height=1200)

<div style="font-size: 0.9em;"><div style="width: calc(100% - 30px); box-shadow: none; border: thin solid rgb(229, 229, 229);"><div style="padding: 5px;"><div><p><strong>Sign up for Dash Club</strong> → Free cheat sheets plus updates from Chris Parmer and Adam Schroeder delivered to your inbox every two months. Includes tips and tricks, community apps, and deep dives into the Dash architecture. <u><a href="https://go.plotly.com/dash-club?utm_source=Dash+Club+2022&utm_medium=graphing_libraries&utm_content=inline">Join now</a></u>.</p></div></div></div></div>

Pattern Fills

New in v5.7

Area charts afford the use of patterns (also known as hatching or texture) in addition to color:

python

import plotly.express as px
df = px.data.medals_long()

fig = px.area(df, x="medal", y="count", color="nation",
             pattern_shape="nation", pattern_shape_sequence=[".", "x", "+"])
fig.show()

Filled area chart with plotly.graph_objects

Basic Overlaid Area Chart

python

import plotly.graph_objects as go

fig = go.Figure()
fig.add_trace(go.Scatter(x=[1, 2, 3, 4], y=[0, 2, 3, 5], fill='tozeroy')) # fill down to xaxis
fig.add_trace(go.Scatter(x=[1, 2, 3, 4], y=[3, 5, 1, 7], fill='tonexty')) # fill to trace0 y

fig.show()

Overlaid Area Chart Without Boundary Lines

python

import plotly.graph_objects as go

fig = go.Figure()
fig.add_trace(go.Scatter(x=[1, 2, 3, 4], y=[0, 2, 3, 5], fill='tozeroy',
                    mode='none' # override default markers+lines
                    ))
fig.add_trace(go.Scatter(x=[1, 2, 3, 4], y=[3, 5, 1, 7], fill='tonexty',
                    mode= 'none'))

fig.show()

Interior Filling for Area Chart

python

import plotly.graph_objects as go

fig = go.Figure()
fig.add_trace(go.Scatter(x=[1, 2, 3, 4], y=[3, 4, 8, 3],
    fill=None,
    mode='lines',
    line_color='indigo',
    ))
fig.add_trace(go.Scatter(
    x=[1, 2, 3, 4],
    y=[1, 6, 2, 6],
    fill='tonexty', # fill area between trace0 and trace1
    mode='lines', line_color='indigo'))

fig.show()

Gradient Fill

New in 5.20

Scatter traces with a fill support a fillgradient, which is a dict of options that defines the gradient. Use fillgradient.colorscale to define the colorscale for the gradient and choose a type to define the orientation of the gradient ('horizontal', 'vertical' or 'radial').

In the following example, we've defined a horizontal fillgradient with a colorscale of three colors.

python

import plotly.graph_objects as go

fig = go.Figure(
    [
        go.Scatter(
            x=[1, 2, 3, 4],
            y=[3, 4, 8, 3],
            fill=None,
            mode="lines",
            line_color="darkblue",
        ),
        go.Scatter(
            x=[1, 2, 3, 4],
            y=[1, 6, 2, 6],
            fill="tonexty",
            mode="lines",
            line_color="darkblue",
            fillgradient=dict(
                type="horizontal",
                colorscale=[(0.0, "darkblue"), (0.5, "royalblue"), (1.0, "cyan")],
            ),
        ),
    ]
)

fig.show()

Stacked Area Chart

The stackgroup parameter is used to add the y values of the different traces in the same group. Traces in the same group fill up to the next trace of the group.

python

import plotly.graph_objects as go

x=['Winter', 'Spring', 'Summer', 'Fall']

fig = go.Figure()
fig.add_trace(go.Scatter(
    x=x, y=[40, 60, 40, 10],
    hoverinfo='x+y',
    mode='lines',
    line=dict(width=0.5, color='rgb(131, 90, 241)'),
    stackgroup='one' # define stack group
))
fig.add_trace(go.Scatter(
    x=x, y=[20, 10, 10, 60],
    hoverinfo='x+y',
    mode='lines',
    line=dict(width=0.5, color='rgb(111, 231, 219)'),
    stackgroup='one'
))
fig.add_trace(go.Scatter(
    x=x, y=[40, 30, 50, 30],
    hoverinfo='x+y',
    mode='lines',
    line=dict(width=0.5, color='rgb(184, 247, 212)'),
    stackgroup='one'
))

fig.update_layout(yaxis_range=(0, 100))
fig.show()

Stacked Area Chart with Normalized Values

python

import plotly.graph_objects as go

x=['Winter', 'Spring', 'Summer', 'Fall']
fig = go.Figure()

fig.add_trace(go.Scatter(
    x=x, y=[40, 20, 30, 40],
    mode='lines',
    line=dict(width=0.5, color='rgb(184, 247, 212)'),
    stackgroup='one',
    groupnorm='percent' # sets the normalization for the sum of the stackgroup
))
fig.add_trace(go.Scatter(
    x=x, y=[50, 70, 40, 60],
    mode='lines',
    line=dict(width=0.5, color='rgb(111, 231, 219)'),
    stackgroup='one'
))
fig.add_trace(go.Scatter(
    x=x, y=[70, 80, 60, 70],
    mode='lines',
    line=dict(width=0.5, color='rgb(127, 166, 238)'),
    stackgroup='one'
))
fig.add_trace(go.Scatter(
    x=x, y=[100, 100, 100, 100],
    mode='lines',
    line=dict(width=0.5, color='rgb(131, 90, 241)'),
    stackgroup='one'
))

fig.update_layout(
    showlegend=True,
    xaxis_type='category',
    yaxis=dict(
        type='linear',
        range=[1, 100],
        ticksuffix='%'))

fig.show()

Select Hover Points

python

import plotly.graph_objects as go

fig = go.Figure()
fig.add_trace(go.Scatter(x=[0,0.5,1,1.5,2], y=[0,1,2,1,0],
                    fill='toself', fillcolor='darkviolet',
                    hoveron = 'points+fills', # select where hover is active
                    line_color='darkviolet',
                    text="Points + Fills",
                    hoverinfo = 'text+x+y'))

fig.add_trace(go.Scatter(x=[3,3.5,4,4.5,5], y=[0,1,2,1,0],
                    fill='toself', fillcolor = 'violet',
                    hoveron='points',
                    line_color='violet',
                    text="Points only",
                    hoverinfo='text+x+y'))

fig.update_layout(
    title = "hover on <i>points</i> or <i>fill</i>",
    xaxis_range = [0,5.2],
    yaxis_range = [0,3]
)

fig.show()

Reference

See https://plotly.com/python/reference/scatter/#scatter-line and https://plotly.com/python/reference/scatter/#scatter-fill for more information and attribute options!