Get Latitude and Longitude from EXIF using PIL

get_lat_lon_exif_pil.py

import PIL.Image
from PIL.ExifTags import TAGS, GPSTAGS
from operator import mul

def rekey(d, source):
    """Re-keys a dictionary d to use keynames from source mapping."""
    return {encoding.get(k, k):v for (k, v) in d.iteritems()} if d else {}


def get_exif(image):
    """Returns a dictionary from the exif data of an PIL Image item. Also converts the GPS Tags"""
    exif = rekey(image._getexif(), TAGS)
    exif['GPSInfo'] = rekey(exif.get('GPSInfo'), GPSTAGS)
    return exif


def dms_to_float(ll):
    """Exif lat/long is a tuple of degrees, minutes, seconds,
        e.g. ((51, 1), (29, 1), (3108, 100))
        Convert that to a floating point number of degrees.
    """
    to_float = lambda x: float(x[0]) / float(x[1])
    dot = lambda x, y: sum(map(mul, x, y))
    return dot(map(to_float, ll), [1, 1/60.0, 1/3600.0])


def get_gps(exif):
    """returns lat, lng from exif dict."""
    gps = exif['GPSInfo']
    sign = lambda k: 1 if gps.get(k + 'Ref') in {'N', 'E'} else -1
    read = lambda k: dms_to_float(gps[k]) * sign(k)
    return map(read, ['GPSLatitude', 'GPSLongitude'])


def main(filename):
    image = PIL.Image.open(filename)
    exif = get_exif(image)
    lat, lng = get_gps(exif)
    print("lat/lng for %s is (%f, %f)" % (filename, lat, lng))