Observation date different from picture date

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Platform (Android, iOS, Website): Android

App version number, if a mobile app issue (shown under Settings or About): 1.27.7 (549)

Browser, if a website issue (Firefox, Chrome, etc) :

URLs (aka web addresses) of any relevant observations or pages:

Screenshots of what you are seeing (instructions for taking a screenshot on computers and mobile devices: https://www.take-a-screenshot.org/):



Description of problem (please provide a set of steps we can use to replicate the issue, and make as many as you need.): The last observations I have made have a date which is not the date of the pictures in my phone. Until now it has always worked for me. Now the date is january 2003. When I check the hour and date on my phone there’s no problem so I don’t understand.

Step 1:

Step 2:

Step 3:

There is this “GPS date stamp” attribute in the photo metadata, and it shows that incorrect date for some reason.

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It only shows this in iNaturalist. Look on the screenshot of my picture, the date is correct.

Because that date is taken from a different metadata attribute.

Not sure if the problem is related, but I found here a similar thread https://forum.inaturalist.org/t/possible-date-time-unix-epoch-issue-with-samsung-phones/17453

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Please where can you see this attribute? Thanks

I’m not totally sure why, but iNat chooses to use GPS_DATE_STAMP, and only uses the DATE_TIME_ORIGINAL if it doesn’t find the GPS_DATE_STAMP.

It looks like Samsung is giving the wrong GPS_DATE_STAMP for your photo even though the DATE_TIME_ORIGINAL is correct.

https://www.inaturalist.org/photos/228903405

image

image

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Ok so for some reason, few days ago, my phone started to take pictures with incorrects GPS DATE STAMP. But why? And how can I make it save the real date?
Thanks

Maybe Samsung updated firmware or something? I can only guess.

I don’t think there is a great solution. You can turn off geotagging on your photos and allow the app to pull the location directly from the phone’s GPS. You can use the website to bulk edit photos to the correct date after uploading with the app (it won’t be able to find the real date, you’d have to enter it manually). You can transfer your photos to a computer and use the web uploader, which doesn’t rely on the GPS Date Stamp. You can open the web uploader in your mobile browser.

@kueda may also be willing to modify the iNat code to deal with Samsung’s error

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That date difference looks like the 1024-week cycle of the GPS satellite system. Which means the GPS chip in your phone, and/or your phone’s software, must have stopped correcting for it. Don’t know how old your phone is, but it may need a software/firmware update to correct the problem.

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Thank you for your help! I just updated my OS and now it works.

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Actually it still doesn’t work…

You are right, my phone (Samsung Galaxy S9 Plus) has a GPS week number rollover issue. The problem is I don’t know how to fix it.
iNaturalist seems to use GPS date when the picture contains location metadata. Otherwise it uses the normal date of the image. But why doesn’t it always use this date?

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That is a question that the iNat developers would have to answer and possibly change - they have already been tagged in on this topic.

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Thanks for quickly sleuthing this one, especially @jwidness. I’ve made an issue and hopefully we can get this fixed before long.

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Since the GPS date is theoretically more reliable (when properly handled) than the user-changeable phone/camera date, I’m wondering if instead of abandoning GPS date, it would be worth iNat handling and correcting bad GPS dates internally. (This probably won’t be the last time that a phone or camera manufacturer fails to do so.)

I did this very thing when my vintage 2010 (but otherwise very nice) GPS unit stopped handling the week number roll-over about a year ago. Just wrote a short bit of code to:

  1. check for difference of at least 1023 weeks between GPS date and current date (or, for this case, it would compare the phone/camera date),
  2. if difference detected, assume the later of the two dates reflects the correct GPS epoch, and
  3. increment the GPS date by 1024 weeks to bring it to the correct epoch.