I notice that in the posting "https://exiftool.org/forum/index.php?topic=11199.0" that the .gpx data extracted is shown as being UTC/GMT with the suffix "Z", e.g. using the sample video produced as:
<trkpt lat="37.7540933333333" lon="-122.424983333333">
</trkpt>
Now the time stamp coincides with the display time on the screen which is very likely local time and not Z time. If so, has anyone found the location of the GMT offset that is set during the camera setup?
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If the data was saved in the file, Phil would have seen it and it would be extracted. The sample video in that post doesn't include such data.
If the time zone was known, a work around would be to edit the gpx.fmt file to add the ShiftTime helper function. Using the sample file from that post, which would have been in an -07:00 time zone, you would have to add 7 hours to get to UTC.
In the gpx.fmt file you would change <time>${gpsdatetime#;my ($ss)
into <time>${gpsdatetime#;ShiftTime('+7);my ($ss)
For other time zones, replace the +7 with the negated value of the correct time zone, i.e. negative time zones would have a positive number, positive time zones would have a negative number.
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Yes, agree - but the fundamental problem is that we have no way of knowing if local time has been set correctly. If it has then the above will work, as would using the lat and long to work back to GMT. The only positive method of establishing GMT is for the camera to take GMT from the satellite and write it to the file. The problem I have is trying to reliability correlate many files back to a known reference. This can be done with NEMA type files, but apparently not with Novatek files?
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
I notice that in the posting "https://exiftool.org/forum/index.php?topic=11199.0" that the .gpx data extracted is shown as being UTC/GMT with the suffix "Z", e.g. using the sample video produced as:
<trkpt lat="37.7540933333333" lon="-122.424983333333">
</trkpt>
Now the time stamp coincides with the display time on the screen which is very likely local time and not Z time. If so, has anyone found the location of the GMT offset that is set during the camera setup?
If the data was saved in the file, Phil would have seen it and it would be extracted. The sample video in that post doesn't include such data.
If the time zone was known, a work around would be to edit the
gpx.fmtfile to add theShiftTimehelper function. Using the sample file from that post, which would have been in an-07:00time zone, you would have to add 7 hours to get to UTC.In the
gpx.fmtfile you would change<time>${gpsdatetime#;my ($ss)into
<time>${gpsdatetime#;ShiftTime('+7);my ($ss)For other time zones, replace the
+7with the negated value of the correct time zone, i.e. negative time zones would have a positive number, positive time zones would have a negative number.Yes, agree - but the fundamental problem is that we have no way of knowing if local time has been set correctly. If it has then the above will work, as would using the lat and long to work back to GMT. The only positive method of establishing GMT is for the camera to take GMT from the satellite and write it to the file. The problem I have is trying to reliability correlate many files back to a known reference. This can be done with NEMA type files, but apparently not with Novatek files?