can't seem to set GPS Lat/Lon after '-keys:GPSCoordinates<GPSPosition'

[bobo]

Hi,

I am trying to set keys:GPSCoordinates from the GPSPosition. I noticed that after setting this field, I can no longer update the default mapped -GPSLatitude=0.00 --GPSLongitude=0.00

First I set to 0/0, things are working.

exiftool '-GPSLatitude=0.00 -GPSLatitudeRef=0.00' '-GPSLongitude=0.00 -GPSLongitudeRef=0.00'  test.MOV -verbose
    1 image files updated
GPS Version ID                  : 2.3.0.0
GPS Latitude                    : 0 deg 0' 0.00" N
GPS Longitude                   : 0 deg 0' 0.00" E
GPS Latitude Ref                : North
GPS Longitude Ref               : East
GPS Position                    : 0 deg 0' 0.00" N, 0 deg 0' 0.00" E

Then I set to 5/3, things are working.

exiftool '-GPSLatitude=5.00 -GPSLatitudeRef=5.00' '-GPSLongitude=3.00 -GPSLongitudeRef=3.00' test.MOV -verbose
    1 image files updated
GPS Version ID                  : 2.3.0.0
GPS Latitude                    : 5 deg 5' 0.00" N
GPS Longitude                   : 3 deg 3' 0.00" E
GPS Latitude Ref                : North
GPS Longitude Ref               : East
GPS Position                    : 5 deg 5' 0.00" N, 3 deg 3' 0.00" E

As a sanity check I repeat the previous two more times to make sure that things are working.

Now I set the key based on the GPSPosition

exiftool '-keys:GPSCoordinates<GPSPosition' test.MOV -verbose
    1 image files updated

GPS Version ID                  : 2.3.0.0
GPS Coordinates                 : 5 deg 5' 0.00" N, 3 deg 3' 0.00" E
GPS Latitude                    : 5 deg 5' 0.00" N
GPS Longitude                   : 3 deg 3' 0.00" E
GPS Latitude Ref                : North
GPS Longitude Ref               : East
GPS Position                    : 5 deg 5' 0.00" N, 3 deg 3' 0.00" E


Great, it worked. However at this point, I can no longer updates GPS Latitude or Longitude.

Questions:
1 - is this because exiftool now has multiple GPS fields available and it doesn't know which to pick?
2 - if so, why is there no warning or error message - the indication is that the file was updated successfully.


exiftool '-GPSLatitude=0.00 -GPSLatitudeRef=0.00' '-GPSLongitude=0.00 -GPSLongitudeRef=0.00' test.MOV -verbose
1 image files updated
GPS Version ID                  : 2.3.0.0
GPS Coordinates                 : 5 deg 5' 0.00" N, 3 deg 3' 0.00" E
GPS Latitude                    : 5 deg 5' 0.00" N
GPS Longitude                   : 3 deg 3' 0.00" E
GPS Latitude Ref                : North
GPS Longitude Ref               : East
GPS Position                    : 5 deg 5' 0.00" N, 3 deg 3' 0.00" E


I get the impression that this is a newbie misunderstanding.

Using ExifTool 12.05 on Mac OSX 10.15.2, ZSH shell

Thank you,

- Borna

[Phil Harvey]

Hi Borna,

This is FAQ 3

- Phil

[StarGeek]

To break things down further

Code Select Expand

C:\>exiftool -P -overwrite_original -GPSLatitude=5.00 -GPSLatitudeRef=5.00 -GPSLongitude=3.00 -GPSLongitudeRef=3.00 Y:\!temp\Test1.mp4
    1 image files updated

C:\>exiftool -g1 -a -s -gps* Y:\!temp\Test1.mp4
---- XMP-exif ----
GPSLatitude                     : 5 deg 0' 0.00" N
GPSLongitude                    : 3 deg 0' 0.00" E
---- Composite ----
GPSLatitudeRef                  : North
GPSLongitudeRef                 : East
GPSPosition                     : 5 deg 0' 0.00" N, 3 deg 0' 0.00" E

Here you can see that you set the XMP:GPSLatitude/XMP:GPSLongitude.  The XMP GPS tags are meant to include the reference direction, as there are not XMP GPS reference tags.  As you can see, setting GPSLatitudeRef/GPSLongitudeRef in your original command did nothing.  The composite reference tags are derived from the XMP tags.  You can verify this by setting the main tags to a hemisphere opposite of the reference tags.  For example

Code Select Expand

C:\>exiftool -P -overwrite_original -GPSLatitude=-5.00 -GPSLatitudeRef=N -GPSLongitude=-5.00 -GPSLongitudeRef=E Y:\!temp\Test1.mp4
    1 image files updated

C:\>exiftool -g1 -a -s -gps* Y:\!temp\Test1.mp4
---- XMP-exif ----
GPSLatitude                     : 5 deg 0' 0.00" S
GPSLongitude                    : 5 deg 0' 0.00" W
---- Composite ----
GPSLatitudeRef                  : South
GPSLongitudeRef                 : West
GPSPosition                     : 5 deg 0' 0.00" S, 5 deg 0' 0.00" W

Even though I set the references to North and East, the output shows South and West.

Now going back to your original command and then setting the Quicktime tag

Code Select Expand

C:\>exiftool -P -overwrite_original -GPSLatitude=5.00 -GPSLongitude=3.00 Y:\!temp\Test1.mp4
    1 image files updated

C:\>exiftool -P -overwrite_original "-keys:GPSCoordinates<GPSPosition" Y:\!temp\Test1.mp4
    1 image files updated

C:\>exiftool -g1 -a -s -gps* Y:\!temp\Test1.mp4
---- Keys ----
GPSCoordinates                  : 5 deg 0' 0.00" N, 3 deg 0' 0.00" E
---- XMP-exif ----
GPSLatitude[tt]GPSLatitude[/tt]/[tt]GPSLongitude[/tt]                     : 5 deg 0' 0.00" N
GPSLongitude                    : 3 deg 0' 0.00" E
---- Composite ----
GPSLatitude                     : 5 deg 0' 0.00" N
GPSLongitude                    : 3 deg 0' 0.00" E
GPSLatitudeRef                  : North
GPSLongitudeRef                 : East
GPSPosition                     : 5 deg 0' 0.00" N, 3 deg 0' 0.00" E

Next, when you re-write the GPSLatitude/GPSLongitude and display the output

Code Select Expand

C:\>exiftool -P -overwrite_original -GPSLatitude=0.00 -GPSLatitudeRef=0.00 -GPSLongitude=0.00 -GPSLongitudeRef=0.00 Y:\!temp\Test1.mp4
    1 image files updated

C:\>exiftool -g1 -a -s -gps* Y:\!temp\Test1.mp4
---- Keys ----
GPSCoordinates                  : 5 deg 0' 0.00" N, 3 deg 0' 0.00" E
---- XMP-exif ----
GPSLatitude                     : 0 deg 0' 0.00" N
GPSLongitude                    : 0 deg 0' 0.00" E
---- Composite ----
GPSLatitude                     : 5 deg 0' 0.00" N
GPSLongitude                    : 3 deg 0' 0.00" E
GPSLatitudeRef                  : North
GPSLongitudeRef                 : East
GPSPosition                     : 5 deg 0' 0.00" N, 3 deg 0' 0.00" E

You can see that you did change the GPSLatitude/GPSLongitude, but the composite tags are derived from the GPSCoordinates tag instead of the XMP tags.

[Phil Harvey]

StarGeek is always showing me up with his detailed answers.

[StarGeek]

Because I have fun trying to explain the details, hopefully in an (semi-)easy to understand way and not in a patronizing way.

[bobo]

Patronizing answers are required in society to get people to help themselves 

Non patronizing ones are also required to help people get going.

I appreciate both!

I was doing something like this:

exiftool test.MOV | grep GPS

Which was printing GPSLatitude the composit tag ... okay, I think I'm starting to get the hang of this tool.

Thanks,

- Borna

[StarGeek]

Take a look at my examples to see how to use a wildcard to skip the extra step of using grep.