228 lines
7.3 KiB
Python
228 lines
7.3 KiB
Python
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import datetime
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import struct # Only to catch struct.error due to error in PIL / Pillow.
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from PIL import Image
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from PIL.ExifTags import TAGS, GPSTAGS
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# Original: https://gist.github.com/erans/983821
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# License: MIT
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# Credits: https://gist.github.com/erans
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class ExifException(Exception):
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def __init__(self, message):
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self._message = message
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def __str__(self):
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return self._message
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class PILExifReader:
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def __init__(self, filepath):
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self._filepath = filepath
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image = Image.open(filepath)
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self._exif = self.get_exif_data(image)
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image.close()
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def get_exif_data(self, image):
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"""Returns a dictionary from the exif data of an PIL Image
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item. Also converts the GPS Tags"""
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exif_data = {}
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try:
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info = image._getexif()
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except OverflowError, e:
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if e.message == "cannot fit 'long' into an index-sized integer":
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# Error in PIL when exif data is corrupt.
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return None
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else:
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raise e
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except struct.error as e:
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if e.message == "unpack requires a string argument of length 2":
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# Error in PIL when exif data is corrupt.
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return None
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else:
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raise e
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if info:
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for tag, value in info.items():
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decoded = TAGS.get(tag, tag)
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if decoded == "GPSInfo":
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gps_data = {}
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for t in value:
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sub_decoded = GPSTAGS.get(t, t)
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gps_data[sub_decoded] = value[t]
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exif_data[decoded] = gps_data
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else:
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exif_data[decoded] = value
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return exif_data
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def read_capture_time(self):
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time_tag = "DateTimeOriginal"
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# read and format capture time
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if self._exif == None:
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print "Exif is none."
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if time_tag in self._exif:
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capture_time = self._exif[time_tag]
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capture_time = capture_time.replace(" ","_")
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capture_time = capture_time.replace(":","_")
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else:
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print "No time tag in "+self._filepath
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capture_time = 0
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# return as datetime object
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return datetime.datetime.strptime(capture_time, '%Y_%m_%d_%H_%M_%S')
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def _get_if_exist(self, data, key):
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if key in data:
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return data[key]
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else:
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return None
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def _convert_to_degress(self, value):
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"""Helper function to convert the GPS coordinates stored in
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the EXIF to degrees in float format."""
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d0 = value[0][0]
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d1 = value[0][1]
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d = float(d0) / float(d1)
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m0 = value[1][0]
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m1 = value[1][1]
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m = float(m0) / float(m1)
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s0 = value[2][0]
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s1 = value[2][1]
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s = float(s0) / float(s1)
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return d + (m / 60.0) + (s / 3600.0)
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def get_lat_lon(self):
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"""Returns the latitude and longitude, if available, from the
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provided exif_data (obtained through get_exif_data above)."""
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lat = None
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lon = None
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gps_info = self.get_gps_info()
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if gps_info is None:
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return None
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gps_latitude = self._get_if_exist(gps_info, "GPSLatitude")
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gps_latitude_ref = self._get_if_exist(gps_info, 'GPSLatitudeRef')
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gps_longitude = self._get_if_exist(gps_info, 'GPSLongitude')
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gps_longitude_ref = self._get_if_exist(gps_info, 'GPSLongitudeRef')
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if (gps_latitude and gps_latitude_ref
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and gps_longitude and gps_longitude_ref):
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lat = self._convert_to_degress(gps_latitude)
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if gps_latitude_ref != "N":
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lat = 0 - lat
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lon = self._convert_to_degress(gps_longitude)
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if gps_longitude_ref != "E":
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lon = 0 - lon
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if isinstance(lat, float) and isinstance(lon, float):
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return lat, lon
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else:
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return None
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def calc_tuple(self, tup):
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if tup is None or len(tup) != 2 or tup[1] == 0:
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return None
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return int(tup[0]) / int(tup[1])
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def get_gps_info(self):
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if self._exif is None or not "GPSInfo" in self._exif:
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return None
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else:
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return self._exif["GPSInfo"]
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def get_rotation(self):
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"""Returns the direction of the GPS receiver in degrees."""
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gps_info = self.get_gps_info()
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if gps_info is None:
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return None
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for tag in ('GPSImgDirection', 'GPSTrack'):
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gps_direction = self._get_if_exist(gps_info, tag)
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direction = self.calc_tuple(gps_direction)
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if direction == None:
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continue
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else:
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return direction
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return None
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def get_speed(self):
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"""Returns the GPS speed in km/h or None if it does not exists."""
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gps_info = self.get_gps_info()
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if gps_info is None:
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return None
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if not "GPSSpeed" in gps_info or not "GPSSpeedRef" in gps_info:
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return None
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speed_frac = gps_info["GPSSpeed"]
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speed_ref = gps_info["GPSSpeedRef"]
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speed = self.calc_tuple(speed_frac)
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if speed is None or speed_ref is None:
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return None
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speed_ref = speed_ref.lower()
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if speed_ref == "k":
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pass # km/h - we are happy.
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elif speed_ref == "m":
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#Miles pr. hour => km/h
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speed *= 1.609344
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elif speed_ref == "n":
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# Knots => km/h
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speed *= 1.852
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else:
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print "Warning: Unknown format for GPS speed '%s' in '%s'." % (
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speed_ref, self._filepath)
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print "Please file a bug and attache the image."
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return None
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return speed
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def is_ok_num(self, val, minVal, maxVal):
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try:
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num = int(val)
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except ValueError:
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return False
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if num < minVal or num > maxVal:
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return False
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return True
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def get_time(self):
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# Example data
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# GPSTimeStamp': ((9, 1), (14, 1), (9000, 1000))
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# 'GPSDateStamp': u'2015:05:17'
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gps_info = self.get_gps_info()
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if gps_info is None:
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return None
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if not 'GPSTimeStamp' in gps_info or not 'GPSDateStamp' in gps_info:
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return None
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timestamp = gps_info['GPSTimeStamp']
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datestamp = gps_info['GPSDateStamp']
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if len(timestamp) != 3:
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raise ExifException("Timestamp does not have length 3: %s" %
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len(timestamp))
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(timeH, timeM, timeS) = timestamp
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h = self.calc_tuple(timeH)
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m = self.calc_tuple(timeM)
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s = self.calc_tuple(timeS)
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if None in (h, m, s):
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raise ExifException(
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"Hour, minute or second is not valid: '%s':'%s':'%s'." %
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(timeH, timeM, timeS))
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if datestamp.count(':') != 2:
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raise ExifException("Datestamp does not contain 2 colons: '%s'" %
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datestamp)
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(y, mon, d) = [int(str) for str in datestamp.split(':')]
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if not self.is_ok_num(y, 1970, 2100) or not self.is_ok_num(
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mon, 1, 12) or not self.is_ok_num(d, 1, 31):
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raise ExifException(
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"Date parsed from the following is not OK: '%s'" % datestamp)
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return datetime.datetime(y, mon, d, h, m, s)
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