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Geotagging JPEG with pyexiv2

I am geotagging JPEG using the pyexiv2 Python module using the code I found in another SO answer (see: What is the best way to use geotag jpeg images using Python? ) And I have a question about GPSTag value.

The code provided in the answer has the following lines:

exiv_image["Exif.Image.GPSTag"] = 654
exiv_image["Exif.GPSInfo.GPSMapDatum"] = "WGS-84"
exiv_image["Exif.GPSInfo.GPSVersionID"] = '2 0 0 0'

I looked at the Exiv2 documentation and found descriptions of GPSTag, GPSMapDatum and GPSVersionID, but I'm still confused about the meaning for GPSTag.

From the documentation it says:

Pointer to IFD GPS Info. The IFF GPS Info functionality interaction structure, like Exif IFD, does not contain image data.

This description does not really explain how to determine which value to use, and I could not find the best GPSTag description on the Internet.

, :

  • , Exif.Image.GPSTag?
  • 654 ( )?

.

+5
2

pyexiv2 , GottenGeography; -)

, GPS pyexiv2, :

    GPS = 'Exif.GPSInfo.GPS'
    try:
        self.latitude = dms_to_decimal(
            *self.exif[GPS + 'Latitude'].value +
            [self.exif[GPS + 'LatitudeRef'].value]
        )
        self.longitude = dms_to_decimal(
            *self.exif[GPS + 'Longitude'].value +
            [self.exif[GPS + 'LongitudeRef'].value]
        )
    except KeyError:
        pass
    try:
        self.altitude = float(self.exif[GPS + 'Altitude'].value)
        if int(self.exif[GPS + 'AltitudeRef'].value) > 0:
            self.altitude *= -1
    except KeyError:
        pass

:

    self.exif[GPS + 'AltitudeRef']  = '0' if self.altitude >= 0 else '1'
    self.exif[GPS + 'Altitude']     = Fraction(self.altitude)
    self.exif[GPS + 'Latitude']     = decimal_to_dms(self.latitude)
    self.exif[GPS + 'LatitudeRef']  = 'N' if self.latitude >= 0 else 'S'
    self.exif[GPS + 'Longitude']    = decimal_to_dms(self.longitude)
    self.exif[GPS + 'LongitudeRef'] = 'E' if self.longitude >= 0 else 'W'
    self.exif[GPS + 'MapDatum']     = 'WGS-84'

:

class Fraction(fractions.Fraction):
    """Only create Fractions from floats.

    >>> Fraction(0.3)
    Fraction(3, 10)
    >>> Fraction(1.1)
    Fraction(11, 10)
    """

    def __new__(cls, value, ignore=None):
        """Should be compatible with Python 2.6, though untested."""
        return fractions.Fraction.from_float(value).limit_denominator(99999)

def dms_to_decimal(degrees, minutes, seconds, sign=' '):
    """Convert degrees, minutes, seconds into decimal degrees.

    >>> dms_to_decimal(10, 10, 10)
    10.169444444444444
    >>> dms_to_decimal(8, 9, 10, 'S')
    -8.152777777777779
    """
    return (-1 if sign[0] in 'SWsw' else 1) * (
        float(degrees)        +
        float(minutes) / 60   +
        float(seconds) / 3600
    )


def decimal_to_dms(decimal):
    """Convert decimal degrees into degrees, minutes, seconds.

    >>> decimal_to_dms(50.445891)
    [Fraction(50, 1), Fraction(26, 1), Fraction(113019, 2500)]
    >>> decimal_to_dms(-125.976893)
    [Fraction(125, 1), Fraction(58, 1), Fraction(92037, 2500)]
    """
    remainder, degrees = math.modf(abs(decimal))
    remainder, minutes = math.modf(remainder * 60)
    return [Fraction(n) for n in (degrees, minutes, remainder * 60)]

pyexiv2, GObject exiv2-, GExiv2, . gexiv2 pyexiv2 exiv2, , pyexiv2 - , python *; gexiv2 , Shotwell.

, !

* pyexiv2 author, Olivier Tilloy, has asked me for help with maintainership as he no longer has much time
+3

, ...

from fractions import Fraction
import pyexiv2

try:
    metadata = pyexiv2.metadata.ImageMetadata(image_file)
    metadata.read();
    thumb = metadata.exif_thumbnail

    try:
        latitude = metadata.__getitem__("Exif.GPSInfo.GPSLatitude")
        latitudeRef = metadata.__getitem__("Exif.GPSInfo.GPSLatitudeRef")
        longitude = metadata.__getitem__("Exif.GPSInfo.GPSLongitude")
        longitudeRef = metadata.__getitem__("Exif.GPSInfo.GPSLongitudeRef")

        latitude = str(latitude).split("=")[1][1:-1].split(" ");
        latitude = map(lambda f: str(float(Fraction(f))), latitude)
        latitude = latitude[0] + u"\u00b0" + latitude[1] + "'" + latitude[2] + '"' + " " + str(latitudeRef).split("=")[1][1:-1]

        longitude = str(longitude).split("=")[1][1:-1].split(" ");
        longitude = map(lambda f: str(float(Fraction(f))), longitude)
        longitude = longitude[0] + u"\u00b0" + longitude[1] + "'" + longitude[2] + '"' + " " + str(longitudeRef).split("=")[1][1:-1]

        latitude_value = dms_to_decimal(*metadata.__getitem__("Exif.GPSInfo.GPSLatitude").value + [metadata.__getitem__("Exif.GPSInfo.GPSLatitudeRef").value]);
        longitude_value = dms_to_decimal(*metadata.__getitem__("Exif.GPSInfo.GPSLongitude").value + [metadata.__getitem__("Exif.GPSInfo.GPSLongitudeRef").value]);

        print "--- GPS ---"
        print "Coordinates: " + latitude + ", " + longitude
        print "Coordinates: " + str(latitude_value) + ", " + str(longitude_value)
        print "--- GPS ---"
    except Exception, e:
        print "No GPS Information!"
        #print e

    # Check for thumbnail
    if(thumb.data == ""):
        print "No thumbnail!"
except Exception, e:
    print "Error processing image..."
    print e;
0

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