I am using the following code to extract the geolocation of an image taken with an iPhone:
from PIL import Image
from PIL.ExifTags import TAGS
def get_exif(fn):
ret = {}
i = Image.open(fn)
info = i._getexif()
for tag, value in info.items():
decoded = TAGS.get(tag, tag)
ret[decoded] = value
return ret
a = get_exif('photo2.jpg')
print a
This is the result that I am returned:
{
'YResolution': (4718592, 65536),
41986: 0,
41987: 0,
41990: 0,
'Make': 'Apple',
'Flash': 32,
'ResolutionUnit': 2,
'GPSInfo': {
1: 'N',
2: ((32, 1), (4571, 100), (0, 1)),
3: 'W',
4: ((117, 1), (878, 100), (0, 1)),
7: ((21, 1), (47, 1), (3712, 100))
},
'MeteringMode': 1,
'XResolution': (4718592, 65536),
'ExposureProgram': 2,
'ColorSpace': 1,
'ExifImageWidth': 1600,
'DateTimeDigitized': '2011:03:01 13:47:39',
'ApertureValue': (4281, 1441),
316: 'Mac OS X 10.6.6',
'SensingMethod': 2,
'FNumber': (14, 5),
'DateTimeOriginal': '2011:03:01 13:47:39',
'ComponentsConfiguration': '\x01\x02\x03\x00',
'ExifOffset': 254,
'ExifImageHeight': 1200,
'Model': 'iPhone 3G',
'DateTime': '2011:03:03 10:37:32',
'Software': 'QuickTime 7.6.6',
'Orientation': 1,
'FlashPixVersion': '0100',
'YCbCrPositioning': 1,
'ExifVersion': '0220'
}
So, I am wondering how I convert the GPSInfo values (DMS) to Decimal Degrees for actual coordinates? Also, there seems to be two Wests listed . . . ?
Here's a way to do it, adapted for a script I wrote some months ago using pyexiv2:
a = get_exif('photo2.jpg')
lat = [float(x)/float(y) for x, y in a['GPSInfo'][2]]
latref = a['GPSInfo'][1]
lon = [float(x)/float(y) for x, y in a['GPSInfo'][4]]
lonref = a['GPSInfo'][3]
lat = lat[0] + lat[1]/60 + lat[2]/3600
lon = lon[0] + lon[1]/60 + lon[2]/3600
if latref == 'S':
lat = -lat
if lonref == 'W':
lon = -lon
This gives me the following latitude and longitude for your picture: 32.7618333, -117.146333 (same results as Lance Lee).
The last entry of GPSInfo may be the heading of the picture. You could check this using a tool that gives proper names to the different EXIF values such as exiv2 or exiftools.
http://www.exiv2.org/tags.html find the string 'Exif.GPSInfo.GPSLatitude' in that page. It appears that you get 3 pairs (representing rationals) and the second number in the pair is the denominator. I would expect the thing after Longitude to be altitude, however it is a better fit for GPS timestamp.
In this example:
32/1 + (4571 / 100)/60 + (0 / 1)/3600 = 32.761833 N
117/1 + (878 / 100)/60 + (0 / 1)/3600 = 117.146333 W
Was this picture taken near 4646 Park Blvd, San Diego, CA 92116? If not then ignore this answer.
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