Convert polygons to raster image

json2jpg.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Thu Oct  3 10:46:28 2019

@author: shino
"""

from shapely import wkt
import json
import pylab as plt
import numpy as np
from matplotlib.path import Path
from PIL import Image


width, height=1024, 1024
finalgt = np.zeros((width, height))


path = "/path/to/labels/"
filename = path + "guatemala-volcano_00000000_pre_disaster.json"
outpath= path + "guatemala-volcano_00000000_pre_disaster.jpg"


file = open(filename, 'r')
json = json.load(file)


for i in json['features']['xy']:
    geom = wkt.loads(i['wkt'])
    pts = list(geom.exterior.coords)
     
    poly_path=Path(pts)

#    print(poly_path)
    x, y = np.mgrid[:height, :width]

    coors = (np.hstack((x.reshape(-1, 1), y.reshape(-1,1))))# coors.shape is (4000000,2)

    mask = poly_path.contains_points(coors)
#    print(mask)
    finalgt = np.where(mask.reshape(height, width) == True,255,finalgt)
#    print(pts)

plt.imshow(finalgt.reshape(height, width))
plt.show()
pilImg = Image.fromarray(np.uint8(finalgt))
pilImg.save(outpath, 'JPEG')