A sript for extracting satellite images of city capitals using the HERE api.

CitySimilarity.py

import math
def calculate_xy(lat,lon,z):
    latRad = lat * math.pi / 180;
    n = math.pow(2, z);
    xTile = n * ((lon + 180) / 360);
    yTile = n * (1-(math.log(math.tan(latRad) + 1/math.cos(latRad))/math.pi)) / 2;
    return(xTile,yTile)

def get_api_keys(keys_file):
    keys = []
    try:
        with open(keys_file) as f:
            keys.append(f.readline())
            keys.append(f.readline())
        return(keys)
    except FileNotFoundError:
        print("'%s' file not found" % keys_file)

def get_city_image(lat,lon,z,size,filename,keys):
    xTile,yTile = calculate_xy(lat,lon,z)
    xTile = int(xTile)
    yTile = int(yTile)
    url = "https://2.aerial.maps.api.here.com/maptile/2.1/maptile/newest/satellite.day/{}/{}/{}/{}/png8?app_id={}&app_code={}"\
    .format(z,xTile,yTile,size,keys[0][:-1],keys[1][:-1])

    import requests
    r = requests.get(url)
    import io
    import os

    import skimage
    img_stringIO = io.BytesIO(r.content)
    img = skimage.io.imread(img_stringIO)
    from skimage.io import imsave
    imsave(os.path.join('cities',filename),img[:,:,:3])

# Reading the API keys:
keys_file = "keys.txt"
keys = get_api_keys(keys_file)


# Testing with Seattle
Seattle_lat = 47
Seattle_lon = 120

z = 15
size = 256

xTile,yTile = calculate_xy(Seattle_lat,Seattle_lon,z)
xTile = int(xTile)
yTile = int(yTile)

url = "https://2.aerial.maps.api.here.com/maptile/2.1/maptile/newest/satellite.day/{}/{}/{}/{}/png8?app_id={}&app_code={}".format(z,xTile,yTile,size,keys[0][:-1],keys[1][:-1])

print(url)

# load the coordinates from the country capitals
# http://techslides.com/list-of-countries-and-capitals

import pandas as pd
df = pd.read_csv("country-capitals.csv",error_bad_lines=False)

for index, row in df.iterrows():
    get_city_image(row["CapitalLatitude"],row["CapitalLongitude"],z,size,row["CapitalName"]+'.jpg',keys)