from PIL import Image

im = Image.open ( "grid.png" )

pix = im.load ()

lat = -23.108
lon = 158.236

cl0 = 37
ln0 = 24

len_cl = 23 / 15
len_ln = 29 / 15

lat = 90 - int ( lat )
lon = int ( lon ) + 180

lon = int ( cl0 + len_cl * lon )
lat = int ( ln0 + len_ln * lat )

print ( lon, lat )

for i in range ( -2, 3 ) :
    for j in range ( -2, 3 ) :
        pix [ lon + i, lat + j ] = 255, 0, 0

im.save ( "iss_position.png" )