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Re: Total ascent figures

Posted: Fri Jun 14, 2019 2:15 pm
by oldkingog
Sorry for the delay, guys. I must be in a time zone behind you. It's not clear to me what file ends up where, but I'm assuming that the FIT file gets uploaded to Connect. I know I upload the GPX file into Basecamp. The Basecamp elevation data is way off as is the Connect data, unless elevation correction is enabled. The trip computer's 'total elev ascent' and total elev descent' during the activity match both of these files. None of the three seems to have accurate elevation info.

A recent hike shows this in Connect when elevation correction is enabled:

440 ft--Elev Gain
436 ft--Elev Loss
9,092 ft--Min Elev
9,363 ft--Max Elev

When disabled, it shows:

2,677 ft--Elev Gain
2,710 ft--Elev Loss
9,065 ft--Min Elev
9,350 ft--Max Elev

The first set of figures totally makes sense based on the hike I did. The second set of figures was on the trip computer and is about 7x as high.

I sure appreciate you looking in to this!

Re: Total ascent figures

Posted: Fri Jun 14, 2019 2:44 pm
by pedigree1
oldkingog wrote:
Fri Jun 14, 2019 2:15 pm
Sorry for the delay, guys. I must be in a time zone behind you. It's not clear to me what file ends up where, but I'm assuming that the FIT file gets uploaded to Connect. I know I upload the GPX file into Basecamp. The Basecamp elevation data is way off as is the Connect data, unless elevation correction is enabled. The trip computer's 'total elev ascent' and total elev descent' during the activity match both of these files. None of the three seems to have accurate elevation info.

A recent hike shows this in Connect when elevation correction is enabled:

440 ft--Elev Gain
436 ft--Elev Loss
9,092 ft--Min Elev
9,363 ft--Max Elev

When disabled, it shows:

2,677 ft--Elev Gain
2,710 ft--Elev Loss
9,065 ft--Min Elev
9,350 ft--Max Elev

The first set of figures totally makes sense based on the hike I did. The second set of figures was on the trip computer and is about 7x as high.

I sure appreciate you looking in to this!
Garmin Connect does indeed take the fit file, automatically when you sync your unit. Elevation correction enables Connect to ignore the Barometric data and use topographic data based on the gps location. That's why the corrected figures are probably about right but leaves me wondering why they bother putting a barometer in there. That's also why Garmin support believe there is a hardware fault with the barometer (at least that's what they have suggested to me). The unit itself is clearly using the barometric data with no corrections applied.

Re: Total ascent figures

Posted: Fri Jun 14, 2019 2:50 pm
by oldkingog
The barometer at least seems to take an accurate reading of current elevation at a moment in time. It seems like the software, though, takes into account subtle changes in barometric readings and includes all theses small increases and decreases into the total elevation gain/loss.

Re: Total ascent figures

Posted: Fri Jun 14, 2019 2:57 pm
by pedigree1
oldkingog wrote:
Fri Jun 14, 2019 2:50 pm
The barometer at least seems to take an accurate reading of current elevation at a moment in time. It seems like the software, though, takes into account subtle changes in barometric readings and includes all theses small increases and decreases into the total elevation gain/loss.
Agreed.

Re: Total ascent figures

Posted: Fri Jun 14, 2019 4:40 pm
by gpsrchive
Would y'all be so kind as to share your 'Setup > Altimeter' settings with me also?

Thank You!

Re: Total ascent figures

Posted: Fri Jun 14, 2019 5:10 pm
by oldkingog
gpsrchive wrote:
Fri Jun 14, 2019 4:40 pm
Would y'all be so kind as to share your 'Setup > Altimeter' settings with me also?

Thank You!
Mine are:

Auto Calibration -- Once
Barometer Mode -- Variable Elevation
Pressure Trending -- Save when power on
Plot Type -- Elevation/Distance

Re: Total ascent figures

Posted: Fri Jun 14, 2019 5:43 pm
by pedigree1
Mine are the same as oldkingog. I have been thinking of changing to continuous calibration, but in the interests of changing one thing at a time, have not done this yet.

Re: Total ascent figures

Posted: Fri Jun 14, 2019 5:50 pm
by gpsrchive
Great, those are the same settings I use on my GPSMAP 66.

We are going to do some testing recording GPX and FIT files while monitoring the Trip Computer, Recording Controls, and Altimeter pages, then additional comparisons will be made using BaseCamp and various online track analyzers. When we have something to report, we will do so here.

Re: Total ascent figures

Posted: Fri Jun 14, 2019 6:04 pm
by pedigree1
Many thanks.

Re: Total ascent figures

Posted: Fri Jun 14, 2019 7:11 pm
by oldkingog
Grateful for your work! I look forward to hearing what you learn...