910XT questions
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KathleenKP
Posts: 580 Member
I finally set up my Garmin Connect account and uploaded the data from my watch. Oh, boy. This is going to take a while to work through.
I notice that it says my elevation gain for yesterday's ride was over 2300 feet. Our group leader told us it was 1600. What do I go with? (I think he plans it on RidewithGPS) I've also noticed the elevation on my watch likes to jump around a lot.
I'm sure I'll have more Qs later.
I notice that it says my elevation gain for yesterday's ride was over 2300 feet. Our group leader told us it was 1600. What do I go with? (I think he plans it on RidewithGPS) I've also noticed the elevation on my watch likes to jump around a lot.
I'm sure I'll have more Qs later.
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Replies
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Garmin watches get their elevation information from linking with the satellites. They base their elevation info by how far away the watch is from certain satellites at any given time. Which is kind of cool to stop and ponder. The problem is, as the satellites move, the corrections made by your watch don't come quick enough. I used to, for grins and giggles, put my watch on the elevation data screen then sit on my front porch and watch it go up and down. Simply sitting there, I could get readings that varied as much as 25 feet.
Which of course meant that the elevation part of my rides and runs were greatly exaggerated.
GC tries to correct this on yourworkout's data page. If you scroll down to the bottom of your ride page, there's a part that should say "Additional Information". If you click on the little triangular arrow it should tell you which Garmin device was used to capture your data. Underneath that it should say "Course corrections" and "Enabled/Disabled". If you click on the "Enabled" portion that should make your runs/rides more accurate, from an elevation standpoint.
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This is what GC says about the "Course Corrections" doo-dad:
What are Elevation Corrections?
Elevation Corrections cross reference the horizontal position (latitude/longitude) provided by the GPS with elevation data that has been acquired by professional surveys. When corrections to elevation data are made, each trackpoint of your activity now contains the elevation from the web service, not the elevation provided by your GPS device.
Garmin Connect selectively applies corrections to depict a more realistic representation of your elevation experience. Activities recorded from devices without a barometric altimeter are enabled with Elevation Corrections by default. Alternatively, activities recorded by devices with a barometric altimeter generally contain accurate elevation data and therefore Elevation Corrections are disabled by default. For those users who are familiar with the MotionBased Gravity service, this is the same service.
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I hope this helps, and it's good to see that you got yourself set up on GC. It's a data junkie's dream.0 -
Thanks, Joe! I freaked a little when it told me it was going to take over 3 hours to transfer all the data. It did take a long time, but not three hours. (It was over an hour, though.) Then, not being a data junkie, I stayed up until the wee hours of the morning checking out different things and editing my workouts...
That's interesting how their info says the devices with the barometric altimeter are more accurate - and yet you and I can just sit there and watch the elevation change. (I have stood in one place to watch the elevation bounce around.)
I'm off to see about that data correction.0 -
It dropped the elevation gain to 1300 - lost a whole 1,000 ft!! Which is a massive percentage. But I think that number is more in line with past data I've been given about our rides. I also changed the Lake Stevens course I rode last week from "enabled" to "disabled" and went from 6,000 ft to 3,400 ft.
Too bad the Garmin is so far off in it's accuracy. I mean...isn't that point of Garmin?
So Garmin, who is supposed to be a leader in pinpoint location data, goes out to the web to collect data someone else has put together and uses that to correct the bad data it gives? The accuracy of it's elevation data was one of the features I was most wanting in this watch.
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Actually, the 910XT uses an barometer (air pressure) altimeter, not GPS based like the older models. The barometer is way more accurate than GPS but not 100%.Garmin watches get their elevation information from linking with the satellites. They base their elevation info by how far away the watch is from certain satellites at any given time. Which is kind of cool to stop and ponder. The problem is, as the satellites move, the corrections made by your watch don't come quick enough. I used to, for grins and giggles, put my watch on the elevation data screen then sit on my front porch and watch it go up and down. Simply sitting there, I could get readings that varied as much as 25 feet.
Which of course meant that the elevation part of my rides and runs were greatly exaggerated.
GC tries to correct this on yourworkout's data page. If you scroll down to the bottom of your ride page, there's a part that should say "Additional Information". If you click on the little triangular arrow it should tell you which Garmin device was used to capture your data. Underneath that it should say "Course corrections" and "Enabled/Disabled". If you click on the "Enabled" portion that should make your runs/rides more accurate, from an elevation standpoint.
************
This is what GC says about the "Course Corrections" doo-dad:
What are Elevation Corrections?
Elevation Corrections cross reference the horizontal position (latitude/longitude) provided by the GPS with elevation data that has been acquired by professional surveys. When corrections to elevation data are made, each trackpoint of your activity now contains the elevation from the web service, not the elevation provided by your GPS device.
Garmin Connect selectively applies corrections to depict a more realistic representation of your elevation experience. Activities recorded from devices without a barometric altimeter are enabled with Elevation Corrections by default. Alternatively, activities recorded by devices with a barometric altimeter generally contain accurate elevation data and therefore Elevation Corrections are disabled by default. For those users who are familiar with the MotionBased Gravity service, this is the same service.
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I hope this helps, and it's good to see that you got yourself set up on GC. It's a data junkie's dream.0
