I don’t think the problem is the with the gpx as I have this shift at other places, with an open sky.
Yes it’s difficult to say how many time it occurs, perhaps 10 times, perhaps more. And the shift is not clear, it’s more like a progressive delay, so it’s difficult to split the sequence.
I’ve already manually corrected the images from a 6500 pictures sequence. It took me 10 or 20 hours. I won’t do it another time.
If I have to take 3 or 4 hours to have a better sequence, I could do it, but if it takes days of work, I will delete the sequence.
When I’ve corrected the location of my 6500 pictures sequence, I used the Photoadjust plugin in Josm. But with this plugin, you move the pictures one by one. If you could select several pictures and move them together, it will save a lot of time.
Another tool could be useful when like me, you geotag the picture from your action cam with a gpx :
With a long sequence, you could have a drift between the gps clock and the action cam clock. This tool would be able to rewrite the exif time to sync it with the gps clock.
BTW : I really don’t know what happened with this sequence. It was my first one with the Xiaomi Yi, and I don’t know if the culprit is the cam or the gpx.