latng2tile.py

import math
from time import sleep
from urllib.request import Request, urlopen
from PIL import Image

ZOOM_SIZE = 16	
TILE_SIZE = 256
TILE_URL = "https://a.tile.openstreetmap.org/{}/{}/{}.png"

def deg2num(lat_deg, lon_deg, zoom):
  lat_rad = math.radians(lat_deg)
  n = 2.0 ** zoom
  xtile = (lon_deg + 180.0) / 360.0 * n
  ytile = (1.0 - math.asinh(math.tan(lat_rad)) / math.pi) / 2.0 * n
  return (xtile, ytile)

def get_img(x, y):
  request = Request(TILE_URL.format(ZOOM_SIZE, x, y))
  request.add_header('User-Agent', 'Maptthing')
  return urlopen(request)

def stitch(lat, lng):
  xtile, ytile = deg2num(lat, lng, ZOOM_SIZE)
  print(f"{xtile}, {ytile}")
  stitched = Image.new('RGB', (TILE_SIZE * 3, TILE_SIZE * 3))
  for i, x in enumerate(range(int(xtile-1), int(xtile+2))):
    for j, y in enumerate(range(int(ytile-1), int(ytile+2))):
      sleep(1)
      img = Image.open(get_img(x, y))
      print(f"saving at {x} at {i*TILE_SIZE}, {y} at {j*TILE_SIZE}")
      stitched.paste(img, box=(i*TILE_SIZE, j*TILE_SIZE))
  xoffset = xtile - (x - (TILE_SIZE * 2)) + (xtile % 1)
  yoffset = ytile - (y - (TILE_SIZE * 2)) + (ytile % 1)
  print(f"cropping: from {xoffset} {yoffset}")
  box = (xoffset - TILE_SIZE / 2, yoffset - TILE_SIZE / 2, xoffset + TILE_SIZE / 2, yoffset + TILE_SIZE /2)
  print(f"box: {box}")
  cropped = stitched.crop(box)
  cropped.save('out.png')


stitch(51.471539,-0.0931495)

def stitch2(lat, lng):
    xtile, ytile = deg2num(lat, lng, ZOOM_SIZE)
    print(f"{xtile}, {ytile}")
    stitched = Image.new('RGB', (TILE_SIZE * 3, TILE_SIZE * 3))
    for i, x in enumerate(range(int(xtile-1), int(xtile+2))):
        for j, y in enumerate(range(int(ytile-1), int(ytile+2))):
            sleep(1)
            img = Image.open(get_img(x, y))
            print(f"saving at {x} at {i*TILE_SIZE}, {y} at {j*TILE_SIZE}")
            stitched.paste(img, box=(i*TILE_SIZE, j*TILE_SIZE))
    xoffset, yoffset = (xtile%1 - 0.5)*TILE_SIZE+TILE_SIZE*3/2, (ytile%1 - 0.5)*TILE_SIZE+TILE_SIZE*3/2
    print(f"cropping: from {xoffset} {yoffset}")
    box = (xoffset - TILE_SIZE / 2, yoffset - TILE_SIZE / 2, xoffset + TILE_SIZE / 2, yoffset + TILE_SIZE /2)
    print(f"box: {box}")
    cropped = stitched.crop(box)
#     cropped.save('out.png')
    return cropped