Hi,
I did a hike and according to google maps and OsmAnd it is about 18km long. I've uploaded the gpx data to the watch and followd the track.
UltraTrac was on till about 3:30 than I changed to GPS+Galileo. From this time on it looks a bit better. The problem starts when you go really slow or having a stop. At 2:10 was a longer stop at the summit. Then the GPS signal just goes crazy and jumps. This will create some extra kilometer which you have actually not done. The watch recorded > 26km.
Is there a way to edit a the data and upload it again?
You can see the activity here: Gullfjelstoppen
The weather was perfect, no tree cover, no buldings, no nothing.