Hi all
I'm trying to do geotagging with a high degree of accuracy. I have GPX tracks with positions recorded in one second intervals. Specifically, I want to achieve the following
goals:
- For geotagging not only considering the camera time offset, but also the camera time drift (based on pictures of the time display of the GPS logger)
- Rewrite the timestamps of the picture with the time-drift corrected
- Due to drift-correction, calculated picture positions may naturally fall between recorded GPX-positions. However, since I prefer having untagged pictures over inaccurately tagged ones, there shall be no geotagging happening if there aren't GPX points just before/after (< 1s) the calculated capture time.
I have the following draft for a command:
exiftool \
-v2 \
-api GeoMaxIntSecs=1 `# goal 3` \
-api GeoMaxExtSecs=1 `# goal 3` \
-geosync='06:40:10@2016:06:29 06:40:22' `# goal 1` \
-geosync='09:20:54@2016:06:30 09:21:30' `# goal 1` \
-'Geotime<${CreateDate}+05:30' `# set timezone` \
-geotag 'track.gpx' \
-'AllDates<${CreateDate}' `# goal 2` \
-overwrite_original mypics/
My questions:
- The line -'AllDates<${CreateDate}' for achieving goal 2 seems to rewrite the original capture time, not the drift-corrected one. I tried variants with Geotime, Geodate and Geotag, but none seem to work. How can I fix this?
- Are the options for achieving goals 1 and 3 correct?
Thank you for your help.
Well done. You've got goals 1 and 3 correct. For goal 2, I would recommend copying GPSDateTime back to another date/time tag in a second command (this is the only date/time that will be drift corrected by the -geotag option). If you write to an EXIF tag, you will have to correct for time zone (you can use the -globalTimeShift option for this).
- Phil