GPSrChive Discussion Forum

Hi
How does Your total ascent elevation works?
It looks like it sums GPS data and not barometer readings, since values are greater than real.
The elevation saved in file are correct (barometer), so one can calculate total ascent in some app, but I couldn't find a way to change how device calculate it on fly (GPS vs baro) and display on screen.

Please be more specific - providing screen captures and saved *.FIT / *.GPX files for inspection.

I have compared Garmin with my Holux GPS tracker that uses barometer for elevation data and smart watch (don't know if it has barometer).
Total gain on Garmin was 600 m and on other devices 350-400 m.
Garmin app also show about 600 m gain, but when You put GPX to other aps like Strava or GPS Visualizer they calculate about 350-450 m (depends on elev. gain threshold).


Garmin GPX in zip file:

One issue here is that each software will use different criteria to determine total elevation gain/loss, and the results will vary depending on how each application is configured. So, none of them are any more correct or less correct than the other. They are all correct based on their configuration.

I wanted to inspect the GPX file from your GPSr, but the file you provided is not from the GPSr, it is from Garmin Connect, so it has been modified from the original.

If you want to submit another session, please provide unedited GPX file from the GPSr for inspection.

Thank You!

OK, here is GPX directly from Garmin BaseCamp.


I have checked indoor, that it uses barometer for elevation calculation. Having poor GPS signal showing elevation jumping 0-300 m, elevation gain stayed at 0 for 20 minutes and when I started moving Garmin up and down in room it counted correctly gains of 1-2 m.
So it looks like it may count gains every second with every 0,01 m of high change (errors), but we can't see it in GPX because it saves only minor changes?

PS. I have made GPS tracker with barometer and other stuff some time ago and I put option to set what should be the difference in height to count it as gain and add to total gain.

Unfortunately, no matter which program, application or web service you share the file from, it will no longer be the same file that the device recorded, that is why I requested the GPX directly from the GPSr.

Hi
I have deleted that file on my device so I have to make new tracks.
I have recorded 3 the same tracks. As You can see there are differences in elevation gain (both calculated from recorded data and recorded by Garmin in device).
What I observed is:
- When You walk down the hill and have device in pocket it will always count gain of about 1-3 meters every minute
- Having device in pocket may have affect on counting gain
- Looks like, when is counting gain, it takes every measure error into account. We don't observe it in files or on device screen, since that are filtered data.

Appears you made same trip on multiple days, which is a great test pattern.

All three trips appear to mirror each other pretty well, with only a few small deviations (one was 3.7miles, the other two 3.9 miles).

The data, as displayed in GPS Visualizer is pretty consistent across all three trips.

UPDATE
After one month of Garmin support working on problem, I have received info, that my device is working fine, since elevation plots are the same as real terrain and some errors may be because of low GPS signal... So they don't even understand the problem

I guess we do not understand correctly either.

Your previous post with three different trips all recorded very similar data.

Please, help us understand specifically what the issue is?