Easy OpenStreetMap tile displaying for Python

Question

I want to include the open street map (OSM) in my python code.

I have read through lots of webpages regarding to OSM. But unfortunately I\'m a bit lost, regarding wh

Answer 1

Edit: OpenStreetMap states that their tile servers are not free to use and are under a usage policy:
https://operations.osmfoundation.org/policies/tiles/
Please read this before using the example.

As I had problems implementing the code in Python 3.8, I merged a few of the answers together and modified the code. Now it works for me and I don't get any errors.
When I tried to run the original code from BerndGit in Python 3, I had to make the same changes as Joining Dots described in his answer. I replaced

 import urllib2
 import StringIO

with

import requests
from io import BytesIO

because the urllib2 library doesn't work with Python 3 anymore. You have to use urllib.request or requests.
Then I had to change these two lines from the getImageCluster function

imgstr = urllib2.urlopen(imgurl).read()
tile = Image.open(StringIO.StringIO(imgstr))

to

imgstr = requests.get(imgurl)
tile = Image.open(BytesIO(imgstr.content))

After that I could run the code without errors but it still couldn't download the images. I always got a black tile as a result. Through some research I learned, that it is important to fake a user agent while using requests, as the website could tell that the request is coming from Python and may block it. The following website describes this:
https://www.scrapehero.com/how-to-fake-and-rotate-user-agents-using-python-3/
So I followed the suggestions from the website which resulted in adding this line right at the beginning of the getImageCluster function:

headers = {"User-Agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36"}

Now we need to include these headers into the requests call:

imgstr = requests.get(imgurl, headers=headers)

The whole code looks like this now:

import matplotlib.pyplot as plt
import numpy as np
import math
import requests
from io import BytesIO
from PIL import Image
   
    
    
def deg2num(lat_deg, lon_deg, zoom):
  lat_rad = math.radians(lat_deg)
  n = 2.0 ** zoom
  xtile = int((lon_deg + 180.0) / 360.0 * n)
  ytile = int((1.0 - math.log(math.tan(lat_rad) + (1 / math.cos(lat_rad))) / math.pi) / 2.0 * n)
  return (xtile, ytile)
    
def num2deg(xtile, ytile, zoom):
  n = 2.0 ** zoom
  lon_deg = xtile / n * 360.0 - 180.0
  lat_rad = math.atan(math.sinh(math.pi * (1 - 2 * ytile / n)))
  lat_deg = math.degrees(lat_rad)
  return (lat_deg, lon_deg)
   
def getImageCluster(lat_deg, lon_deg, delta_lat,  delta_long, zoom):
    headers = {"User-Agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36"}
    smurl = r"http://a.tile.openstreetmap.org/{0}/{1}/{2}.png"
    xmin, ymax =deg2num(lat_deg, lon_deg, zoom)
    xmax, ymin =deg2num(lat_deg + delta_lat, lon_deg + delta_long, zoom)
   
    Cluster = Image.new('RGB',((xmax-xmin+1)*256-1,(ymax-ymin+1)*256-1) ) 
    for xtile in range(xmin, xmax+1):
        for ytile in range(ymin,  ymax+1):
            try:
                imgurl = smurl.format(zoom, xtile, ytile)
                print("Opening: " + imgurl)
                imgstr = requests.get(imgurl, headers=headers)
                tile = Image.open(BytesIO(imgstr.content))
                Cluster.paste(tile, box = ((xtile-xmin)*256 ,  (ytile-ymin)*255))
            except: 
                print("Couldn't download image")
                tile = None
   
    return Cluster
    
    
    
if __name__ == '__main__':
    
    a = getImageCluster(38.5, -77.04, 0.02,  0.05, 13)
    fig = plt.figure()
    fig.patch.set_facecolor('white')
    plt.imshow(np.asarray(a))
    plt.show()

The result is the following: