How can I maintain EXIF GPS data when moving/copying or importing photos in multiple formats?

I prefer to edit all metadata outside Photos (and Google Photos) because they both tend to import metadata quite well (but not perfectly) but they tend to keep the metadata edits to themselves unless laborious workarounds are used or exporting re-encoded files. And different versions might behave unexpectedly.

Photos CAN export original unmodified files and XMP sidecar to save the edited (?) IPTC (is it really IPTC or XMP?) metadata. I dislike sidecar files but I guess exiftool should be able to copy the metadata to the original files so that there would no quality loss from re-encoding (with highest quality the quality loss is not visible, though, but the filesize might be larger than the original?). I'll test this later.

GraphicConverter is fine for tagging images, but currently I am using HoudahGeo to tag the photos. I like the list views with the table of metadata. I am using it to add GPS, reverse geocode the locations, adjust the date and time, add titles, descriptions, keywords, before I am importing the originals to Photos. And keep the originals with the Houdahgeo files backed up, because I am no longer trusting Photos to preserve the originals unmodified.

Thanks for the reminder. I have used GraphicConverter since 1990's. I tried HoudahGeo several years ago and it seems it is time to take a look at it again.

Export the photos properly. Drag and Drop or copy and paste will just save previews, possibly with a reduced quality, without metadata attached.

• Select the photos and use "File > Export > Export ... photos". In the export dialog select the highest quality and the original size, and enable the checkmark to include the metadata. This will save the edited versions in a high quality and save the GPS coordinates as well. However, saving as a JPG is currently buggy and does currently not include the title and the keywords on macOS 11, but a TIFF will include all metadata. To export a TIFF - use these export settings, for example:
• 
• Or export the photos as the unmodified originals with "File > export > export unmodified Original". This will include the original metadata, but not the IPTC metadata you added after importing the photos. You should enable the checkmark to create an XPM sidecar file to save the IPTC metadata.

I have used GraphicConverter to rename images and movies based on their EXIF or other metadata (and vice versa to adjust EXIF and movie dates based on file names), and to set EXIF and other dates, locations, ratings, Captions, Keywords, labels, batch custom name suffixes and name changes.

GraphicConverter uses exiftool internally for metadata and I have used exiftool from the command line for some tasks where GC has no GUI. (Some recent GC versions have had trouble with movies if their DST differs from the current DST and the time has then been +-1hour off. The current beta fixed that. But for large batches I have used exiftool to set the movie dates (Keys, UserData, QuickTime, file dates) to my liking).

Just yesterday I used exiftool to filter out old Canon 550D and 6D movies that I have planned to re-encode with ffmpeg to about 15 Mb/s HEVC because they take too much space in their original up to 90 Mb/s H.264 form with PCM audio (I do archive those "raw" files, though). I also used exiftool to filter out movies with largish PCM audio in other movies but I am still undecided whether to re-encode just the audio to mp4a because exiftool shows that the H.264 video in those files is only about 20 Mb/s (they were mainly iPad movies obviously shot with Filmic because other iOS movies used mp4 audio).

I have planned to bake exiftool inside an AppleScript applet so users can use it to get filedates and maybe other metadata with minimum hassle. Frequently someone here asks why their images or movies sort incorrectly and I guess that it would be great help for troubleshooting to see the actual dates. But I am no expert in AppleScript so that project is still unfinished (it works if the user has exiftool installed but usually that is too much to ask eventhough it is just a basic install).

See also:

https://discussions.apple.com/docs/DOC-250002750