Why does Python Choropleth map not display colors?

Question

I would like to create a Choropleth map in Python using Folium library.

This is the dataset:

df_new_count2

Reviewer Country Count Original Number Percentage

0 Greece 191 3352 0.056981

1 Belgium 338 5991 0.056418

2 Germany 429 7843 0.054698

The Json file used is the following: https://s3-api.us-geo.objectstorage.softlayer.net/cf-courses-data/CognitiveClass/DV0101EN/labs/Data_Files/world_countries.json

This is the code I used:

world_map = folium.Map(location=[40, 0], zoom_start=1.5)

folium.Choropleth( geo_data='https://s3-api.us-geo.objectstorage.softlayer.net/cf-courses-data/CognitiveClass/DV0101EN/labs/Data_Files/world_countries.json',

    name='choropleth',

    data=df_new_count2,

    columns=['Reviewer Country','Percentage'],

    key_on='feature.properties.name',

    fill_color='YlOrRd',

    fill_opacity=0.7,

    line_opacity=0.2,

    legend_name='Percentage of people'
).add_to(world_map)

folium.LayerControl().add_to(world_map)

world_map

The map is displaying but everything is black, the colors are not showing.

Map

Does anyone know what the issue might be? Thanks in advance for your time.

Answer 1

You can try:

import pandas as pd
import folium

# create dataframe
df_new_count2 = pd.DataFrame([['Greece', 0.056981], ['Belgium', 0.056418], ['Germany', 0.054698]], columns=['Reviewer Country','Percentage'])
df_new_count2

# plot map
world_map = folium.Map(location=[40, 0], zoom_start=1.5)
folium.Choropleth(geo_data='https://s3-api.us-geo.objectstorage.softlayer.net/cf-courses-data/CognitiveClass/DV0101EN/labs/Data_Files/world_countries.json', name='choropleth',
    data=df_new_count2,
    columns=['Reviewer Country','Percentage'],
    key_on='feature.properties.name',
    fill_color='YlOrRd',
    fill_opacity=0.7,
    line_opacity=0.2,
    legend_name='Percentage of people'
).add_to(world_map)
folium.LayerControl().add_to(world_map)
world_map

Result:

It only colors the countries for which data is available in the dataframe. Can you validate your dataframe contains data for the countries selected?