Using PIL to extract geo (GPS) EXIF data. Extract position from a list of images containing EXIF information. Very poorly written :/

gistfile1.py

#!/usr/bin/env python
# -*- coding: utf-8 -*- 

from PIL import Image
from PIL.ExifTags import TAGS
from pprint import pprint

def get_exif(fn):
    try:
        ret = {}
        i = Image.open(fn)
        info = i._getexif()
        for tag, value in info.items():
            decoded = TAGS.get(tag, tag)
            ret[decoded] = value
        return ret
    except:
        return False

def gps_human_assembly(gps_info):
    """
    {0: (2, 3, 0, 0),
     1: 'N',
     2: ((46, 1), (36, 1), (54774, 1000)),
     3: 'E',
     4: ((101, 1), (46, 1), (36258, 1000)),
     5: 0,
     6: (22442, 10),
     7: ((1, 1), (19, 1), (38000, 1000)),
    """
    lat = gps_info[2]
    lon = gps_info[4]

    lat = str(lat[0][0]) + "° " + str(lat[1][0]) + "' " + str(float(lat[2][0]) / lat[2][1]) + "\" " + gps_info[1]
    lon = str(lon[0][0]) + "° " + str(lon[1][0]) + "' " + str(float(lon[2][0]) / lon[2][1]) + "\" " + gps_info[3]
 
    return lat + ", " + lon

def gps_convert_ddmmss(d, m, s):
    dec_min = (m*1.0 + (s/60.0))
    ans = d*1.0 + (dec_min/60.0)
    return ans

def gps_decimal_degrees(gps_info):
    lat = gps_info[2]
    lon = gps_info[4]
    lat = gps_convert_ddmmss(lat[0][0], lat[1][0], float(lat[2][0]) / lat[2][1])
    lon = gps_convert_ddmmss(lon[0][0], lon[1][0], float(lon[2][0]) / lon[2][1])
    return (round(lat, 6), round(lon, 6))


def look_for_gps_data(fn, pix):
    exif = get_exif(fn)
    if 'GPSInfo' in exif:
        gps_info = exif['GPSInfo']
        d = exif['DateTime']

        if 2 not in gps_info:
            return False
        #pprint(exif)
        return (fn, gps_info, d, pix)
    else:
        return False


def loop_on_dir(path):
    from os import walk
    import os

    f = []
    for (dirpath, dirnames, filenames) in walk(path):
        f.extend(filenames)

    gps_data = []
    for fn in f:
        p = os.path.join(path,fn)
        if get_exif(p):
            data = look_for_gps_data(p, fn)
            if data:
                gps_data.append(data)
    return gps_data

def convert_date(date):
    r = date.split(' ')
    return r[0].replace(':', '-')+"T"+r[1]+"Z"

def create_gpx(gpx_file, gps_data):
    f = open(gpx_file, 'w')

    f.write('<?xml version="1.0" encoding="ISO-8859-1" standalone="yes"?>')
    f.write('<?xml-stylesheet type="text/xsl" href="details.xsl"?>')
    f.write("""
<gpx
 version="1.0"
 creator="Extract exif"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xmlns="http://www.topografix.com/GPX/1/0"
 xmlns:topografix="http://www.topografix.com/GPX/Private/TopoGrafix/0/1" xsi:schemaLocation="http://www.topografix.com/GPX/1/0 http://www.topografix.com/GPX/1/0/gpx.xsd http://www.topografix.com/GPX/Private/TopoGrafix/0/1 http://www.topografix.com/GPX/Private/TopoGrafix/0/1/topografix.xsd">
    """)
    for fn,px,date,pix in gps_data:
        lat, lon = gps_decimal_degrees(px)
        f.write('<wpt lat="' + str(lat) + '" lon="' + str(lon) + '">')
        d = convert_date(date)
        f.write('<time>' + d + '</time>')
        f.write("<name><![CDATA[" + date  + " - " + pix + "]]></name>")
        f.write("<desc><![CDATA[" + pix + "]]></desc>")
        f.write("<sym>Dot</sym>")
        f.write("<type><![CDATA[Dot]]></type>")
        f.write('<ele>100.0</ele>')
        f.write('</wpt>')
    f.write("</gpx>")
     
    f.close()

# MAIN 
gps_data = loop_on_dir("/Users/baptiste/dev/exifpython/img")
create_gpx("test_file.gpx", gps_data)