PYTHON

add legend to px.choropleth map python

from urllib.request import urlopen
import json


with urlopen('https://raw.githubusercontent.com/plotly/datasets/master/geojson-counties-fips.json') as response:
    counties = json.load(response)

import pandas as pd
df = pd.read_csv("https://raw.githubusercontent.com/plotly/datasets/master/fips-unemp-16.csv",
                   dtype={"fips": str})

import plotly.express as px

fig = px.choropleth(df, geojson=counties, locations='fips', color='unemp',
                           color_continuous_scale="Viridis",
                           range_color=(0, 12),
                           scope="usa"
                          )
fig.update_layout(margin={"r":0,"t":0,"l":0,"b":0},coloraxis_colorbar=dict(
    title="unemployment rate",
    thicknessmode="pixels",
    lenmode="pixels",
    yanchor="top",y=1,
    ticks="outside",
    tickvals=[0,4,8,12],
    ticktext=["Low", "Low Medium", "High Medium", "High"],
    dtick=4
))
fig.show()