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User python and piexif to write some gps info into jpg pictures.
import os
import piexif
from fractions import Fraction
def to_deg(value, loc):
"""convert decimal coordinates into degrees, munutes and seconds tuple
Keyword arguments: value is float gps-value, loc is direction list ["S", "N"] or ["W", "E"]
return: tuple like (25, 13, 48.343 ,'N')
"""
if value < 0:
loc_value = loc[0]
elif value > 0:
loc_value = loc[1]
else:
loc_value = ""
abs_value = abs(value)
deg = int(abs_value)
t1 = (abs_value-deg)*60
min = int(t1)
sec = round((t1 - min)* 60, 5)
return (deg, min, sec, loc_value)
def change_to_rational(number):
"""convert a number to rantional
Keyword arguments: number
return: tuple like (1, 2), (numerator, denominator)
"""
f = Fraction(str(number))
return (f.numerator, f.denominator)
def set_gps_location(file_name, lat, lng, altitude):
"""Adds GPS position as EXIF metadata
Keyword arguments:
file_name -- image file
lat -- latitude (as float)
lng -- longitude (as float)
altitude -- altitude (as float)
"""
lat_deg = to_deg(lat, ["S", "N"])
lng_deg = to_deg(lng, ["W", "E"])
exiv_lat = (change_to_rational(lat_deg[0]), change_to_rational(lat_deg[1]), change_to_rational(lat_deg[2]))
exiv_lng = (change_to_rational(lng_deg[0]), change_to_rational(lng_deg[1]), change_to_rational(lng_deg[2]))
gps_ifd = {
piexif.GPSIFD.GPSVersionID: (2, 0, 0, 0),
piexif.GPSIFD.GPSAltitudeRef: 1,
piexif.GPSIFD.GPSAltitude: change_to_rational(round(altitude)),
piexif.GPSIFD.GPSLatitudeRef: lat_deg[3],
piexif.GPSIFD.GPSLatitude: exiv_lat,
piexif.GPSIFD.GPSLongitudeRef: lng_deg[3],
piexif.GPSIFD.GPSLongitude: exiv_lng,
}
exif_dict = {"GPS": gps_ifd}
exif_bytes = piexif.dump(exif_dict)
piexif.insert(exif_bytes, file_name)
@Avi1git

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Avi1git commented Jan 11, 2019

Hi, I want to write transformed coordinates into the exif. Values like 3570178.732528623!

breite = exif_dict['GPS'][piexif.GPSIFD.GPSLatitude]
lange = exif_dict['GPS'][piexif.GPSIFD.GPSLongitude]
 
breite = breite[0][0] / breite[0][1] + breite[1][0] / (breite[1][1] * 60) + breite[2][0] / (breite[2][1] * 3600)
lange = lange[0][0] / lange[0][1] + lange[1][0] / (lange[1][1] * 60) + lange[2][0] / (lange[2][1] * 3600)
x, y = pyproj.transform(wgs84, gk3, lange, breite)

exif_dict['GPS'][piexif.GPSIFD.GPSLatitude] = [ ( (int)(round(y,6) * 1000000), 1000000 ), (0, 1), (0, 1) ]
 
exif_bytes = piexif.dump(exif_dict)

I am getting struct.error: argument out of range in the dump method. Please advise.

@bluems

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bluems commented Apr 8, 2019

@Avi1git Hi.
The Float number your 3570178.732528623 is Rectangular Coordinate System. no GPS.
First, You must study to diffrent GPS and RCS.
You can find if the RCS can not be converted to GPS immediately.

@CalebM1987

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CalebM1987 commented Nov 1, 2019

This works nicely to set/update the coordinates, however, you will lose some of the original Exif Data! What should be done is first fetch the original exif data and then just update the GPS tags:

    gps_exif = {"GPS": gps_ifd}

    # get original exif data first!
    exif_data = piexif.load(file_name)

    # update original exif data to include GPS tag
    exif_data.update(gps_exif)
    exif_bytes = piexif.dump(exif_data)

    piexif.insert(exif_bytes, file_name)

See the two images below where the exif properties on the left are done without fetching the original exif data first, while the ones on the right do get the original exif data first and then just updates the gps tags:

exif_diff1

exif_diff2

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