Hi,
Many devices have the tendency to reset their date/time when they lose power for a moment. If you’re not careful, your device will save the pictures as if they were made in 2016. I didn’t find any step by step guide on how to fix this, so I’ll share the steps here.
The gist of it is that you change the original date with a date close to the GPS date/time. For some reason, Mapillary seems to consume metadata dates in this order: DateTime Original > DateTime Digitized > Modify Date > GPS Date/Time
Why the GPS date is taken last is beyond me, as I’d think that is correct by definition.
Anyway, here goes:
-
Download exiftool
You can download from exiftool.org, but since I was on a work PC, I used the portable version available at Oliver Betz | Artikel / ExifTool Windows installer and portable package
Unzip the file in a folder like C:\whereever-you-like\exif tool\ -
Open a command prompt (hit windows button and start typing “prompt”). Move the active directory by typing:
cd C:\whereever-you-like\exif tool\
(you can paste in the prompt by simply right clicking. You can access previous commands by pushing the “up” key)
- See if things work
For example, let’s start the tool and use it to read the exif data from a single image:
exiftool.exe g:\mapillary\2016\104GOPRO\G0065843.jpg
(note: if you actually installed the exiftool, you won’t need to change the directory to the correct place and can just type exiftool, without the .exe)
- Calculate the time difference between:
GPS Date/Time : 2021:12:11 09:19:22Z
Date/Time Original : 2016:03:03 16:31:20
I didn’t care about the exact time, so I used this: “5:9:8 0:0:0” (5 years, 9 months, 8 days)
- Try it out to fix one image:
exiftool.exe “-DateTimeOriginal+=5:9:8 0:0:0” g:\mapillary\2016\104GOPRO\G0065843.jpg
Note that that will also save a backup of the original image. If you’re satisfied with the result, we can do this in bulk. Don’t forget to not “fix” your test image twice!
- Fix everything in a single folder:
exiftool.exe “-DateTimeOriginal+=5:9:8 0:0:0” g:\mapillary\2016\
Final note: it would be better to simply overwrite the DateTimeOriginal with the GPSDateTime. However, for some reason, exiftool refused to do that when I tried.