How is Total Ascent calculated?

[lukas12p]

1. Device is counting elevation gain "live" and at the same time is writing GPX file with actual elevation.
2. Total elevation gain during/after trip calculated by device is much bigger than elevation gain calculated from elevation data in GPX.
3. Elevation gain is rising even if You go down the hill, adds about 1-3 meters every minute.

So it looks like:
4. Elevation data in GPX is correct, almost the same as real terrain
5. Elevation data in GPX is taking rounded elevation measurements taken only when writing data to file
6. Elevation gain counted by device is taking not rounded elevation measurements every second or even more often. So it can take into account all errors like +/- 10cm every second, but looks more like it only take errors with +

[GPSrChive]

When you state "Elevation gain counted by device", are you referring to what is displayed on the Trip Computer Page?

What setting do you have configured on your Montana 7x0 in Setup > Recording > Advanced Setup > Trip Recording?

[lukas12p]

When you state "Elevation gain counted by device", are you referring to what is displayed on the Trip Computer Page?

What setting do you have configured on your Montana 7x0 in Setup > Recording > Advanced Setup > Trip Recording?

Yes

[GPSrChive]

Please answer the second question.

[lukas12p]

Trip recording -> during activity
Activity type -> track me

[GPSrChive]

OK, so with Trip Recording = During Activity, you are seeing 'Elevation gain counted by device' in the Trip Computer Page does not agree with the recorded track log data (GPX)?

[lukas12p]

OK, so with Trip Recording = During Activity, you are seeing 'Elevation gain counted by device' in the Trip Computer Page does not agree with the recorded track log data (GPX)?

Yes, trip recording is about 20-50% bigger than GPX and reality

[GPSrChive]

OK, and which specific data field are you referring to in the Trip Computer? (I just want to be sure I test exactly what you are looking at)

[lukas12p]

OK, and which specific data field are you referring to in the Trip Computer? (I just want to be sure I test exactly what you are looking at)

Total Ascent