title: Plot colored polygons with geodataframe in folium
body: <p>I'm trying to plot radar data in folium, and I'm almost there. I followed this example (<a href="https://stackoverflow.com/questions/34886899/contour-plot-data-lat-lon-value-within-boundaries-and-export-geojson">Contour plot data (lat,lon,value) within boundaries and export GeoJSON</a>) to get my data into a GeoJson format. </p>
  
  <pre><code>nb_class = 20 
  collec_poly = plt.contourf(lons,lats,np.array(poshdata), nb_class,alpha=0.5)
  
  gdf = collec_to_gdf(collec_poly) # From link above
  gdf.to_json()
  colors = [p.get_facecolor().tolist()[0] for p in collec_poly.collections]
  gdf['RGBA'] = colors
  
  gdf
  </code></pre>
  
  <p>This outputs two columns: geometry and RGBA. </p>
  
  <pre><code>    RGBA    geometry
  0   [0.0, 0.0, 0.713903743316, 1.0] (POLYGON ((-71.57032079644679 42.2775236331535...
  1   [0.0, 0.0960784313725, 1.0, 1.0]    (POLYGON ((-71.56719970703125 42.2721176147460...
  2   [0.0, 0.503921568627, 1.0, 1.0] (POLYGON ((-71.55678558349609 42.2721176147460...
  3   [0.0, 0.896078431373, 0.970904490829, 1.0]  (POLYGON ((-71.52552795410156 42.2849182620049...
  4   [0.325743200506, 1.0, 0.641998734978, 1.0]  (POLYGON ((-71.49427795410156 42.2939676156927...
  5   [0.641998734978, 1.0, 0.325743200506, 1.0]  (POLYGON ((-71.47344207763672 42.3003084448852...
  6   [0.970904490829, 0.959331880901, 0.0, 1.0]  (POLYGON ((-71.26508331298828 42.3200411822557...
  7   [1.0, 0.581699346405, 0.0, 1.0] (POLYGON ((-71.15048217773438 42.3333218460720...
  </code></pre>
  
  <p>From there I make my folium map:</p>
  
  <pre><code>import folium    
  
  # Picked location between Sudbury and Somerville:
  maploc = folium.Map(location=[42.377157,-71.236088],zoom_start=11,tiles="Stamen Toner")
  
  folium.GeoJson(gdf).add_to(maploc)
  </code></pre>
  
  <p>This creates my nice folium map, but the polygons are not colored at all. How do I get the contours to be filled with the right colors? And fix the opacity?</p>
  
  <p><a href="https://i.stack.imgur.com/5pwtT.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/5pwtT.jpg" alt="enter image description here"></a></p>