Total ascent figures

Discussion related to the Garmin GPSMAP 66 series GPSr
oldkingog
Posts: 38
Joined: Tue Jan 08, 2019 6:01 pm

Re: Total ascent figures

Post by oldkingog » 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!

pedigree1
Posts: 19
Joined: Wed Jun 12, 2019 9:48 am

Re: Total ascent figures

Post by pedigree1 » Fri Jun 14, 2019 2:44 pm

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.

oldkingog
Posts: 38
Joined: Tue Jan 08, 2019 6:01 pm

Re: Total ascent figures

Post by oldkingog » 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.

pedigree1
Posts: 19
Joined: Wed Jun 12, 2019 9:48 am

Re: Total ascent figures

Post by pedigree1 » Fri Jun 14, 2019 2:57 pm

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.

gpsrchive
Site Admin
Posts: 631
Joined: Fri Jan 20, 2017 11:29 pm

Re: Total ascent figures

Post by gpsrchive » 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!

oldkingog
Posts: 38
Joined: Tue Jan 08, 2019 6:01 pm

Re: Total ascent figures

Post by oldkingog » Fri Jun 14, 2019 5:10 pm

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

pedigree1
Posts: 19
Joined: Wed Jun 12, 2019 9:48 am

Re: Total ascent figures

Post by pedigree1 » Fri Jun 14, 2019 5:43 pm

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.

gpsrchive
Site Admin
Posts: 631
Joined: Fri Jan 20, 2017 11:29 pm

Re: Total ascent figures

Post by gpsrchive » Fri Jun 14, 2019 5:50 pm

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.

pedigree1
Posts: 19
Joined: Wed Jun 12, 2019 9:48 am

Re: Total ascent figures

Post by pedigree1 » Fri Jun 14, 2019 6:04 pm

Many thanks.

oldkingog
Posts: 38
Joined: Tue Jan 08, 2019 6:01 pm

Re: Total ascent figures

Post by oldkingog » Fri Jun 14, 2019 7:11 pm

Grateful for your work! I look forward to hearing what you learn...

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