matplotlib geopandas plot chloropleth with set bins for colorscheme

Question

How do I set a consistent colorscheme for three axes in the same figure?

The following should be a wholly reproducible example to run the code and get

Answer 1

From geopandas 0.5 onwards you can use a custom scheme defined as scheme="User_Defined" and supply the binning via classification_kwds.

import geopandas as gpd
print(gpd.__version__)   ## 0.5
import numpy as np; np.random.seed(42)
import matplotlib.pyplot as plt 

gdf = gpd.read_file(gpd.datasets.get_path('naturalearth_lowres')) 
gdf['quant']=np.random.rand(len(gdf))*100-20

fig, ax = plt.subplots()

gdf.plot(column='quant', cmap='RdBu', scheme="User_Defined", 
         legend=True, classification_kwds=dict(bins=[-10,20,30,50,70]),
         ax=ax)

plt.show()

So the remaining task is to get a list of bins from the quantiles of one of the columns. This should be easily done, e.g. via

import mapclassify
bins = mapclassify.Quantiles(gdf['quant'], k=5).bins

then setting classification_kwds=dict(bins=bins) in the above code.