GJ_area_centroids.py

import json
from shapely.geometry import Polygon
from shapely.geometry import MultiPolygon

with open("all_simplified.geojson") as f:
    data = json.load(f)

for feature in data['features']:
    print feature['properties']['GEOID']

    if feature['geometry']['type'] == "MultiPolygon":

        polys = []
        for coordinateSet in feature['geometry']['coordinates']:
            
            for coordinate in coordinateSet:
                if len(coordinate) > 0:
                    polygon = Polygon(coordinate)
                    polys.append(polygon)

        mPolygon = MultiPolygon(polys)
        print feature['properties']['GEOID']+"," + str(mPolygon.area) + "," + str(mPolygon.centroid.x) + "," + str(mPolygon.centroid.y)
    else:

        for coordinate in feature['geometry']['coordinates']:

            if len(coordinate) > 0:
                polygon = Polygon(coordinate)
                print feature['properties']['GEOID']+"," + str(polygon.area) + "," + str(polygon.centroid.x) + "," + str(polygon.centroid.y)