GPS coordinates are not deleted

[frankdarwin]

I have MP4 files to which I assigned wrong GPS coordinates and a wrong location (see "MP4 with GPS Coordinates.jpg").
To delete the wrong data I deleted them in the metadata (see "MP4 after delete GPS Coordinates.jpg").
Now the MP4 files shows a pencil to indicate that metadata must be written back.
Clicking on the pencil shows me what data needs to be written (see "List of Tags to write.jpg").
After I have written metadata, the metadata is updated and the coordinates I just deleted are back.
I can't get rid of the coordinates.

What am I doing wrong?

[Mario]

Check the ExifTool output panel and/or the log file.
Maybe ExifTool has problems updating the metadata in the MP4 and reports it to the output panel and log file?
This would provide a minimum of information to work with.

Or maybe you did not follow the recommendations about how to switch from external XMP sidecar files to embedded XMP metadata for MP4 files? I've explained that in the release notes of the 2021 initial release.

In that case, IMatch now has to deal with embedded XMP and a sidecar file - two sources for XMP. This would explain the problem you are describing.

If you did not read the release notes, I provide the link to the corresponding help topic for your convenience: Importing XMP Metadata

These are the only two reasons I can think of which would cause this problem.

[frankdarwin]

Hello Mario,
I have followed your suggestions.
To have a clean starting situation, I did the following steps:

• Deleted the 2 affected MP4 files in IM.
• Performed a database diagnosis. The DB diagnosis did not bring any errors.
• Imported the 2 MP4 files again. After the import, both files had GPS data again (latitude and longitude, GPS timestamp of 09.10.2022).
• There is no XMP file for the 2 MP4 files.
• ExifTool executed. No errors.
• Latitude and Longitude deleted. After deleting and updating, the data was available again.

In another test, I manually assigned different coordinates to a file by changing Latitude and Longitude. This works.

But when I then deleted the new coordinates again, the original coordinates were present again.

The Metadata Analyst shows the following errors:

[XMP-iptcExt]:LocationShownGPSLatitude not mapped to [XMP-exif]:GPSLatitude (embedded).
[XMP-iptcExt]:LocationShownGPSLongitude not mapped to [XMP-exif]:GPSLongitude (embedded).

In ECP I find the following messages:

[XMP-iptcExt] Location Shown GPS Latitude : 50 deg 56' 56.76 N
[XMP-iptcExt] Location Shown GPS Longitude : 10 deg 2' 7.80 E
[Composite] GPS Latitude : 50 deg 56' 56.76 N
[Composite] GPS Longitude : 10 deg 2' 7.80 E

[Mario]

MP4 has no native GPS data, the only source is XMP. In this case, the embedded XMP data in the MP4.
Double-check that there is no XMP file in the same folder as the MP4 (with the same name as the MP4). A stray XMP file left in the folder would explain the problem.

The log file you have attached shows no trace of IMatch writing metadata to an MP4 file.

Do you perhaps use non-standard metadata settings?
Sometimes users change a setting and then forget about it.
Check Edit > Preferences > Metadata 2, the File Format settings for MP4 on your system etc.

I don't recall another user reporting a similar problem so this is all guesswork.

Do this:

Change the coordinates for the MP4 file in the Metadata Panel or via the Map panel.
Open the ExifTool output panel (The Output Panel)
Write back.
The output panel will show what IMatch is writing via ExifTool and to which file. And if there are any problems reported.
Copy to the contents to the clipboard, paste into Notepad, save as a text file and attach.
Maybe this shows us what the problem is.

You can also upload your problem MP4 file to your cloud space and send me a link to support email address.
Allow for two weeks of processing, though. I get many "My metadata is not working as I expect it to" emails per week and I process these time-consuming support requests when there is idle time. In 99% of all cases, IMatch is right and my personal time was wasted.

If your MP4 works here, the problem is some metadata setting or something other on your PC.
If it produces the same problem here, I can analyze it further.

For testing, I have just set GPS coordinates for a couple MP4 files successfully. Various sources.
I can also change the GPS coordinates in the Map Panel or in the Metadata Panel and write back. The new coordinates always stick. Works OK here. No reports from other users either.

[frankdarwin]

Hello Mario,

there are no XMP files in the same directory as the MP4 file (see "MS Explorer.jpg").

As far as I can tell, I only have default values in the metadata settings.

I changed the coordinates in the Map panel and wrote back the metadata. That worked (see "ExifTool Output change GPS Date with Map Panel.txt).

Then I deleted the new coordinates in the metadata. After that the original coordinates were available again (see "Exif Tool Output delete GPS Date.txt").

I noticed that this problem only occurs with MP4 files that already got the GPS coordinates when recorded with the smartphone.
With MP4 files that have no coordinates saved during recording, everything works fine.

I have sent the link for the download of an affected MP4 file by mail.

I have done all tests on 2 different computers. With the same result. Therefore I exclude a problem on the computer.

I fully understand that the diagnosis may take some time. But would be very happy if you come to a result.

[Mario]

I noticed that this problem only occurs with MP4 files that already got the GPS coordinates when recorded with the smartphone.
With MP4 files that have no coordinates saved during recording, everything works fine.

Interesting. Where does the smart phone store the GPS coordinates? There is no EXIF or GPS record in MP4, AFAIK.

This would also explain why you cannot delete the coordinates by deleting them in XMP. Because while the coordinates are deleted in XMP, ExifTool does not map the "deleted" coordinates back to whatever metadata your smart phone has stored the GPS coordinates initially. And on import ExifTool imports them again into XMP for IMatch.

Or maybe ExifTool cannot delete the GPS coordinates in the file at all. Can happen. I have no idea.
I will look into your files in a week or so and then I can tell you more.

In the mean time, please contact the phone vendor and ask them for software which allows you to erase the GPS coordinates in the video files you have created with your phone. This might be interesting.

[jch2103]

The GPS data may be in the manufacturer's Make Notes. Using the IM Browser metadata pane, my Nikon Z6 records GPS data for videos in the {File.MD.Nikon::NCTG} tag group. My Pixel 6 phone, on the other hand, apparently doesn't record GPS coordinates by default (perhaps this can be enabled in some setting).

@frankdarwin - You may want to try looking for GPS fields using the Browser metadata pane or by doing an ExifTool data dump via the ExifTool Command Processor. 

[Mario]

When I look at the file, I see GPS coordinates in something ExifTool calls "UserData" (whatever proprietary maker note that is) and the synthetic tags ExifTool produces from this data:

Code Select Expand

[UserData]     GPS Coordinates                 : 50 deg 58' 26.40 N, 10 deg 0' 40.68 E
[Composite]    GPS Latitude                    : 50 deg 58' 26.40 N
[Composite]    GPS Longitude                   : 10 deg 0' 40.68 E
[Composite]    GPS Position                    : 50 deg 58' 26.40 N, 10 deg 0' 40.68 E
This is what IMatch uses to set the GPS coordinates of the image and to locate it on the map.
When I change the coordinate and write back, ExifTool produces

Code Select Expand

[UserData]      GPS Coordinates                 : 50 deg 58' 26.40 N, 10 deg 0' 40.68 E
[XMP-iptcExt]   Location Shown GPS Altitude     : 324.290953545232 m, 324.290953545232 m
[XMP-iptcExt]   Location Shown GPS Latitude     : 50 deg 59' 9.06 N, 50 deg 59' 9.06 N
[XMP-iptcExt]   Location Shown GPS Longitude    : 10 deg 0' 28.17 E, 10 deg 0' 28.17 E
[XMP-exif]      GPS Altitude                    : 324.29 m
[XMP-exif]      GPS Altitude Ref                : Above Sea Level
[XMP-exif]      GPS Latitude                    : 50 deg 59' 9.06 N
[XMP-exif]      GPS Longitude                   : 10 deg 0' 28.17 E
[XMP-exif]      GPS Date/Time                   : 2022:10:26 07:11:41
[Composite]     GPS Altitude                    : 324.2 m Above Sea Level
[Composite]     GPS Latitude                    : 50 deg 58' 26.40 N
[Composite]     GPS Longitude                   : 10 deg 0' 40.68 E
[Composite]     GPS Latitude Ref                : North
[Composite]     GPS Longitude Ref               : East
[Composite]     GPS Position                    : 50 deg 58' 26.40 N, 10 deg 0' 40.68 E
When I force IMatch to reload the metadata, the new location sticks, which means ExifTool prefers the XMP coordinates over the UserData coordinates. Very good.

But changing XMP data like clearing XMP GPS lat/lon does not impact the proprietary UserData maker note your camera has written. ExifTool only synchronizes XMP with native EXIF/GPS data, not QuickTime maker notes.

After a bit of pulling, I could figure out how to manually wipe the gps record from the user data:

exiftool -overwrite_original -quicktime:userdata:gpscoordinates= filename

So, again, non-standard metadata written by whatever device software you have used has fucked up your user experience and wasted 30 minutes of my time. Please stick to standard metadata, software and procedures in the future.