Getting KeyError after using "bins" parameter in Choropleth

I tried to do a Choropleth map using Folium. The result was ok but I wanted the colormap to be more “shaded”, since by default there is only 6 bins. However when I set the parameter “bins=10”, I get the error "KeyError: ‘YlGn’ " I noticed I have the same error, when I specify the “bins” parameters in the “Choropleth maps” example of the QuickStart. So I will use this example to illustrate my issue.

The following code:

import folium
import pandas as pd


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)

m = folium.Map(location=[48, -102], zoom_start=3)

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 (%)',
    bins=10
).add_to(m)

folium.LayerControl().add_to(m)

m

Leads to this error :

---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
<ipython-input-6-d2bc56d78020> in <module>
     20     line_opacity=0.2,
     21     legend_name='Unemployment Rate (%)',
---> 22     bins=10
     23 ).add_to(m)
     24 

/usr/local/lib/python3.6/site-packages/folium/features.py in __init__(self, geo_data, data, columns, key_on, bins, fill_color, nan_fill_color, fill_opacity, nan_fill_opacity, line_color, line_weight, line_opacity, name, legend_name, overlay, control, show, topojson, smooth_factor, highlight, **kwargs)
   1088             # We add the colorscale
   1089             nb_bins = len(bin_edges) - 1
-> 1090             color_range = color_brewer(fill_color, n=nb_bins)
   1091             self.color_scale = StepColormap(
   1092                 color_range,

/usr/local/lib/python3.6/site-packages/branca/utilities.py in color_brewer(color_code, n)
    158     if not explicit_scheme:
    159         # Check to make sure that it is not a qualitative scheme.
--> 160         if scheme_info[base_code] == 'Qualitative':
    161             matching_quals = []
    162             for key in schemes:

KeyError: 'YlGn'

The same code without the " bins=10" works perfectly.

What Am I doing wrong here ? Is it because the color_brewer schemes only take 6 values ? What Am I supposed to do then ?

Python version : 3.6.8 Folium Version : ‘0.10.1’

[lorenzoromani1983]

Hi. Is this fixed? I can only plot maps up to 9 bins. More than 9 bins still gives keyerror.

[Conengmo]

I believe this was fixed with https://github.com/python-visualization/branca/pull/115, which was included in branca 0.6.0.