Description

In order to make a choropleth map with folium the data needs to be in a specific format.

https://python-visualization.github.io/folium/quickstart.html#Choropleth-maps

The example from there:

url = 'https://raw.githubusercontent.com/python-visualization/folium/master/examples/data'
state_geo = f'{url}/us-states.json'
state_unemployment = f'{url}/US_Unemployment_Oct2012.csv'
state_data = pd.read_csv(state_unemployment)

The state_geo part is fine, that's just a geojson like we already have.

They use pandas to read the csv of the data. That's a very simple CSV.

Later on the map is generated like this:

folium.Choropleth(
geo_data=state_geo,
name='choropleth',
data=state_data,
columns=['State', 'Unemployment'],
key_on='feature.id',
fill_color='YlGn',
fill_opacity=0.7,
line_opacity=0.2,
legend_name='Unemployment Rate (%)'
).add_to(m)

So the key parts for this work is columns (which defines which columns are taken into consideration) and key_on (which is the place where the geojson features match the first column of the dataset).

They started with CSV so used pandas, but I don't think that's necessary. We just need the same output.