Plotly scatter (bubble plot) marker size in legend

Question

Is there a way to show marker size (bubble size) within the legend of a graph in plotly express (plotly python). For example using the code below, it shows the population using the marker size.

df = px.data.gapminder().query("year==2007")
fig = px.scatter(df, x="gdpPercap", y="lifeExp", color="continent",
    size="pop", size_max=45, log_x=True)
fig.show()

Output:

Matplotlib has something similar using the .legend_elements("sizes") (see here, creating a matplotlib scatter legend size related), was wondering if there is something in Plotly as well.

This is not available at the moment, you can follow this issue to receive updated github.com/plotly/plotly.js/issues/5099 — joelostblom

r-beginners r-beginners · Accepted Answer · 2021-02-14T01:20:05

If you have multiple scatter plots, the size of the legend is basically linked to the size of each marker. As a means of aligning them, you can use the raft setting.API here Offical Reference

fig.update_layout(legend= {'itemsizing': 'trace'})
# Constant: same, Trace: individual marker size

The marker size of your question is a categorical variable, so there is no effect of changing the size.

Plotly scatter (bubble plot) marker size in legend

1 Answers