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pythonpandastopojsonfolium

Folium TopoJSON heatmap does not populate as expected

I am trying to display a folium choropleth heatmap using a custom topoJSON file and a dataframe. The map generates with a uniformly shaded choropleth instead of the expected heatmap.

Heres a snippet of code I am using (excludes basic imports, creation of dataframe):

cols = ['dma', 'values']

center_us_long_lat = [39.50, -98.35]

topo_path = r'../../data/designated_marketing_areas_us_topo.json'

us_map = folium.Map(location=center_us_long_lat,attr='dma_code',
                    tiles='Mapbox Bright', zoom_start=4, min_zoom=4)

us_map.choropleth(geo_path=topo_path, topojson='objects.nielsen_dma',
                  data=df, columns=cols,
                  fill_opacity=0.7,
                  key_on="feature.properties.dma",
                  line_color='white', fill_color='YlOrRd',
                  highlight=True
                 )

The output looks like this:

Output map, not as expected

I've tried adjusting the key_on argument to feature.dma but this results in the same output.

As a reference here's a sample of the df data:

In[1]:
df.head():

Out[1]:
    dma values
1   501 16.749
2   740 8.858
3   807 15.790
4   511 15.315
5   798 8.425

The topojson can be found here

What am I doing wrong? Thanks!

Solution

  • I know this might sound silly, but I always find these issues come down to mismatched data types or leading/lagging spaces. Good luck!