Fetch and untile tiled Himawari-8 images from the http://himawari8.nict.go.jp PNG endpoint, then set them as desktop background on OSX

himawari.py

import os
import requests
from datetime import datetime, timedelta
from PIL import Image
from io import BytesIO
import logging
import argparse


TILE_SIZE = 550

def fetch_image(time, scale, paddings):
    def pathfor(t, x, y):
        return "http://himawari8.nict.go.jp/img/D531106/%sd/550/%s/%02d/%02d/%02d%02d00_%s_%s.png" \
        % (scale, t.year, t.month, t.day, t.hour, (t.minute // 10) * 10, x, y)
    sess = requests.Session()
    png = Image.new('RGB', (TILE_SIZE*scale+paddings[1]+paddings[3], TILE_SIZE*scale+paddings[0]+paddings[2]))
    for x in range(scale):
        for y in range(scale):
            logging.info('Fetching tile {}-{}'.format(x, y))
            path = pathfor(time, x, y)
            tiledata = sess.get(path).content
            tile = Image.open(BytesIO(tiledata))
            png.paste(tile, (TILE_SIZE*x+paddings[3], TILE_SIZE*y+paddings[0],
                             TILE_SIZE*(x+1)+paddings[3], TILE_SIZE*(y+1)+paddings[0]))
    return png


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('--ago', type=int, default=40, help='Fetch images from how many minutes ago')
    parser.add_argument('--scale', type=int, default=8, help='Image scale, from 1 to 16 (powers of 2), and 20')
    parser.add_argument('--padding', default='100,820,100,820', help='Padding')
    parser.add_argument('-v', action='store_true', help='Verbose')
    parser.add_argument('output', help='Output dir')

    args = parser.parse_args()

    if args.v:
        logging.basicConfig(level=logging.INFO)

    time = datetime.utcnow() - timedelta(minutes=args.ago)
    image = fetch_image(time, args.scale, list(map(int, args.padding.split(','))))
    image.save(os.path.join(args.output, time.strftime('%Y%m%d-%H%M') + '.png'))