Some questions regarding geotagging

Software darktable
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1

Hey everyone,

I like telling stories, but if you’re not interested: there is an tl;dr :slight_smile:

I’ve been on a three month travel recently and just trying to get order into my pictures (around 3000). One major part of it is trying to add location data to them. Unfortunately, my setup wasn’t perfect, so the way I try to handle it right now is incredibly tedious.
First of all, I traveled through multiple time zones (and obviously failed to change the camera time every time! - but I have fixed this already). For the first two months, I used a GPS logging application on my phone (https://gpslogger.app/ - can highly recommend it) which outputs daily GPX files. Then my phone broke, so I used my watch to record manually. Unfortunately, my brain is not as trustworthy as the app, so in a lot of cases I started the GPS tracking too late or stopped it and took more photos afterwards. And then there are border crossings. Hitchhiking works splendidly around borders, so I hopped them quite frequently. And with them also time zones. So I have a lot of days, where I need to first separate my pictures into countries and then can apply the locations to them.

So long story short (tl;dr): I have following questions:

  1. Is there a setting, which allows for a ‘goodwill’ in the time. So it applies the start/endpoint of an GPX track to pictures, which have been taken a set time before or after the track was started?
  2. Can I apply multiple GPX files at one time? Even though the GPX file is loaded into a list-like view, whenever I open a new one, the old one is removed. And I also can’t add multiple tracks at one time.
  3. (Probably more a feature suggestion) My GPX tracks are in UTC, my pictures in local time. But when the GPX file is imported, darktable has both times and the location. Wouldn’t it be possible quite easily to automatically detect the timezone of the picture? Or am I missing something?

Thanks in advance
Carroll

2

Most of your questions can be answered by darktable 4.6 user manual - geotagging

But you’ll need to know the correct local time. There is an offset feature in the module that can help.

3

Hi,

I already used the geotagging module to offset the times accordingly.

In the documentation, it refers to a track list. I tried merging my GPX files into one and added it to darktable, which populated it with the independent tracks. Unfortunately, the times where corrupted - I have to revisit my merging script. From everything I tried, I don’t think there is a way to import multiple GPX files, only multiple tracks in one file.

Since the other features are not mentioned in the documentation, I guess they do not exist.
Thank you (: