Converts geojson with polygon features to a JSON blob readable by http://shadowcalculator.eu

shadowcalc.py

#!/usr/bin/env python3
"""
Converts geojson with polygon features to a JSON blob readable by http://shadowcalculator.eu
Usage: ./shadowcalc.py trees.geojson
"""

import sys
import json
import time

data = json.load(open(sys.argv[1]))

shapes = []
for feature in data['features']:
    if feature['geometry']['type'] != 'Polygon':
        continue
    coords = []
    heights = []
    for coord in feature['geometry']['coordinates'][0]:
        coords.append({'lat': coord[1], 'lng': coord[0]})
        heights.append(8)
    shapes.append({'coords': coords, 'heights': heights})

print(json.dumps({
    'shapes': shapes,
    'timestamp': int(time.time() * 1000),
    'mapCenterLat': coords[0]['lat'],
    'mapCenterLng': coords[0]['lng'],
}))