View the original community article here
Last tested: Mar 1, 2018
Quick answer: Upload your topojson file to a gist and put that link into the map_layer_name:
map_layer: custom_manhattan_map {
url: "https://gist.githubusercontent.com/your_user_name/manhattan_tracts.json"
property_key: "ntacode"
}
Remember property_key
is case sensitive.
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