使用 Python 和 Piexif 将 EXIF GPS 数据添加到 .jpg 文件

问题的根源是负经度/纬度值 - 将提供的数据转换为字节格式，而导致错误的行 - 需要无符号值，如 L 参数所示。
从这里的讨论中，您可以看到负值在添加到 exif 之前已转换为正值。还发现了这个将负值转换为正值的例子，同时保持右半/半半 - N/S 或 E/W。我不知道为什么该模块不使用负值 - 一些 EXIF 阅读器也会读取像这样的 N/S E/W 值，而另一些阅读器会忽略它 - 就像您通过右键单击图像获得的 Windows 内置阅读器 -> 属性 ->详细信息。piexifstruct.pack(">L", num)

Phil Harvey 的 ExifTool 将处理负坐标，例如 ，但 piexif 存在负坐标问题。-118.2437

代码中的行生成输出。此嵌套元组中的负值在调用此代码行时会导致问题lon_dms = deg_to_dms(longitude)((-118, 1), (-14, 1), (-37, 1))exif_bytes = piexif.dump(exif_dict)

在下面的代码中，负坐标在函数中被删除。该函数生成的值需要转换为可以使用的格式，这是在函数中完成的。deg_to_dmspiexifdms_to_exif_format

下面的代码仍然需要一些额外的错误处理，也许还需要一些日志记录，以便为生产做好准备。

import piexif
from fractions import Fraction

def deg_to_dms(decimal_coordinate, cardinal_directions):
    """
    This function converts decimal coordinates into the DMS (degrees, minutes and seconds) format.
    It also determines the cardinal direction of the coordinates.

    :param decimal_coordinate: the decimal coordinates, such as 34.0522
    :param cardinal_directions: the locations of the decimal coordinate, such as ["S", "N"] or ["W", "E"]
    :return: degrees, minutes, seconds and compass_direction
    :rtype: int, int, float, string
    """
    if decimal_coordinate < 0:
        compass_direction = cardinal_directions[0]
    elif decimal_coordinate > 0:
        compass_direction = cardinal_directions[1]
    else:
        compass_direction = ""
    degrees = int(abs(decimal_coordinate))
    decimal_minutes = (abs(decimal_coordinate) - degrees) * 60
    minutes = int(decimal_minutes)
    seconds = Fraction((decimal_minutes - minutes) * 60).limit_denominator(100)
    return degrees, minutes, seconds, compass_direction

def dms_to_exif_format(dms_degrees, dms_minutes, dms_seconds):
    """
    This function converts DMS (degrees, minutes and seconds) to values that can
    be used with the EXIF (Exchangeable Image File Format).

    :param dms_degrees: int value for degrees
    :param dms_minutes: int value for minutes
    :param dms_seconds: fractions.Fraction value for seconds
    :return: EXIF values for the provided DMS values
    :rtype: nested tuple
    """
    exif_format = (
        (dms_degrees, 1),
        (dms_minutes, 1),
        (int(dms_seconds.limit_denominator(100).numerator), int(dms_seconds.limit_denominator(100).denominator))
    )
    return exif_format


def add_geolocation(image_path, latitude, longitude):
    """
    This function adds GPS values to an image using the EXIF format.
    This fumction calls the functions deg_to_dms and dms_to_exif_format.

    :param image_path: image to add the GPS data to
    :param latitude: the north–south position coordinate
    :param longitude: the east–west position coordinate
    """
    # converts the latitude and longitude coordinates to DMS
    latitude_dms = deg_to_dms(latitude, ["S", "N"])
    longitude_dms = deg_to_dms(longitude, ["W", "E"])

    # convert the DMS values to EXIF values
    exif_latitude = dms_to_exif_format(latitude_dms[0], latitude_dms[1], latitude_dms[2])
    exif_longitude = dms_to_exif_format(longitude_dms[0], longitude_dms[1], longitude_dms[2])

    try:
        # Load existing EXIF data
        exif_data = piexif.load(image_path)

        # https://exiftool.org/TagNames/GPS.html
        # Create the GPS EXIF data
        coordinates = {
            piexif.GPSIFD.GPSVersionID: (2, 0, 0, 0),
            piexif.GPSIFD.GPSLatitude: exif_latitude,
            piexif.GPSIFD.GPSLatitudeRef: latitude_dms[3],
            piexif.GPSIFD.GPSLongitude: exif_longitude,
            piexif.GPSIFD.GPSLongitudeRef: longitude_dms[3]
        }

        # Update the EXIF data with the GPS information
        exif_data['GPS'] = coordinates

        # Dump the updated EXIF data and insert it into the image
        exif_bytes = piexif.dump(exif_data)
        piexif.insert(exif_bytes, image_path)
        print(f"EXIF data updated successfully for the image {image_path}.")
    except Exception as e:
        print(f"Error: {str(e)}")


latitude = 34.0522
longitude = -118.2437
image_path = '_DSC0075.jpeg'  # Path to your image
add_geolocation(image_path, latitude, longitude)

这是没有 GPS 数据的原始图像：

以下是带有 GPS 数据的修改图像：

这是一个在线实用程序，可用于检查从十进制坐标到 DMS（度、分和秒）坐标的转换。还有一个可以逆转这个过程。