Why are the position values of the GPS information in the image metadata stored as "Composite" by exiftool

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英文:

Why are the position values of the GPS information in the image metadata stored as "Composite" by exiftool

问题

为什么图像元数据中的GPS信息的位置值被存储为“Composite”(复合)?这是因为它们实际上完全属于EXIF 2.32规范的一部分:

来源:https://web.archive.org/web/20190624045241if_/http://www.cipa.jp:80/std/documents/e/DC-008-Translation-2019-E.pdf

英文:

Why are the position values of the GPS information in the image metadata stored as "Composite" by ExifTool 12.57?

E.g.:

image=/path/to/photo.jpg

exiftool -G0 '-gps.*' "${image}"

[EXIF]          GPS Latitude Ref                : North
[EXIF]          GPS Longitude Ref               : East
[EXIF]          GPS Altitude Ref                : Above Sea Level
[EXIF]          GPS Speed Ref                   : km/h
[EXIF]          GPS Speed                       : 0
[EXIF]          GPS Img Direction Ref           : True North
[EXIF]          GPS Img Direction               : 152.5745659
[EXIF]          GPS Dest Bearing Ref            : True North
[EXIF]          GPS Dest Bearing                : 104.1544711
[EXIF]          GPS Date Stamp                  : 2021:10:10
[EXIF]          GPS Horizontal Positioning Error: 44 m
[Composite]     GPS Altitude                    : 102 m Above Sea Level
[Composite]     GPS Latitude                    : 40 deg 41' 5.29" N
[Composite]     GPS Longitude                   : 16 deg 41' 23.70" E
[Composite]     GPS Position                    : 40 deg 41' 5.29" N, 16 deg 41' 23.70" E

I'm asking because they are actually entirely part of the EXIF 2.32 specification:

Why are the position values of the GPS information in the image metadata stored as "Composite" by exiftool

Source: https://web.archive.org/web/20190624045241if_/http://www.cipa.jp:80/std/documents/e/DC-008-Translation-2019-E.pdf

答案1

得分: 1

这是 exiftool FAQ #3

首先,请确保您正在查看正确的信息。使用
ExifTool 使用类似以下命令从文件中提取所有信息,以及写入的位置:

exiftool -a -G1 -s c:\images\test.jpg

在这个命令中,-a 允许提取重复的标签,…

当存在重复的标签时,除非使用 -a 选项,否则只会提取一个。请注意,像 -EXIF:all 这样的选项会选择从提取的标签中选择所有 EXIF 标签,因此在其他位置由重复标签隐藏的 EXIF 标签不会出现在 -EXIF:all 的输出中。

当 exiftool 遇到重复的标签名称并且未使用 -a (-duplicates) 选项,那么显示的标签将是最后读取的标签。复合标签是在读取所有其他标签之后创建的,因此当未使用 -a 选项时,它们将始终列在列表中。

英文:

This is exiftool FAQ #3

> First, make sure you are looking at the right information. Use
> ExifTool with a command like this to extract all information from the
> file, along with the location it was written:
>
> exiftool -a -G1 -s c:\images\test.jpg
>
> In this command, -a allows duplicate tags to be extracted, …

>When duplicate tags exist, only one is extracted unless the -a option is used. Beware that options like -EXIF:all select all EXIF tags from the extracted tags, so EXIF tags hidden by duplicate tags in other locations will not appear in the output for -EXIF:all.

When exiftool encounters a duplicate tag name and the -a (-duplicates) option is not used, then the tag displayed will be that last one read. Composite tags are created last after all the other tags are read, so they will always be the listed ones when -a is not used.

答案2

得分: 0

你可以使用选项 -e--composite 来禁用生成复合标签。这样做将显示原始的EXIF(或其他类别)GPS数值。

复合标签 GPSLatitudeGPSLongitude 是基于众多可能的 GPSLatitude + GPSLatitudeRefGPSLongitude + GPSLongitudeRef 标签(EXIF、XMP、Sony等)生成的,并归一化为使用北东参考,可能会有负值用于南方或西方坐标引用。

GPSPosition 标签是一个复合标签,它是基于归一化的 GPSLatitudeGPSLongitude 生成的,不存在于EXIF标签中。

英文:

You can use the option -e or --composite to disable generation of composite tags. Doing so will show you the original EXIF (or other category) GPS values.

The composite tags GPSLatitude and GPSLongitude are generated based on one of many possible GPSLatitude + GPSLatitudeRef and GPSLongitude + GPSLongitudeRef tags (EXIF, XMP, Sony, ...) and normalized to use North-East reference, with possible negative values for south or west referencing coordinates.

The GPSPosition tag is a composite tag that is generated based on the nomrmalized GPSLatitude and GPSLongitude and doesn't exist as EXIF tag.

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  • 本文由 发表于 2023年3月3日 22:40:15
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