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  1. #1
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    Question about accuracy- is this normal

    So I recently bought a Garmin 810. I've made sure it was set to 1 sec intervals.
    Looking at a portion of one of my rides below, is it normal to be that far off? This is an out and back ride, so I'm riding the exact same trail and a large portion of my ride looks like this. It's the same for the 5 rides I've recorded.
    Thanks for any input.Click image for larger version. 

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  2. #2
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    Seems excessive in my opinion. I'll have times when it's like that, but not consistently, and not for the whole ride. My experience is with Garmin etrex's over the last 6 years or so. North facing and or heavily wooded trails can make it like that, but not for a whole ride. Well, maybe if the whole ride is north facing and heavily wooded. Good luck.
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  3. #3
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    Yeah, I want to see the terrain. Post the actual ride embed widget, not a screen shot.

    It also matters how fast you were going. If you were climbing on one leg and descending balls-out on the other, the climbing leg will have the more accurate GPS track. Based on point spacing, I'm going to suspect this is a large part of what you're seeing. The part on the right appears to have points spaced more closely and would be you riding uphill.

  4. #4
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    It's not normal. But it already happened to me in a forest. For accuracy, GPS devices are less accurate when their are plenty of things surrounding (trees, house, buildings, etc.). Was it your case?

  5. #5
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    Quote Originally Posted by Manu3172 View Post
    It's not normal. But it already happened to me in a forest. For accuracy, GPS devices are less accurate when their are plenty of things surrounding (trees, house, buildings, etc.). Was it your case?
    Yes it is, if you understand how it works.

  6. #6
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    Quote Originally Posted by NateHawk View Post
    Yes it is, if you understand how it works.
    This....

  7. #7
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    Question about accuracy- is this normal

    Quote Originally Posted by NateHawk View Post
    Yeah, I want to see the terrain. Post the actual ride embed widget, not a screen shot.

    It also matters how fast you were going. If you were climbing on one leg and descending balls-out on the other, the climbing leg will have the more accurate GPS track. Based on point spacing, I'm going to suspect this is a large part of what you're seeing. The part on the right appears to have points spaced more closely and would be you riding uphill.
    Agreed, that is not unusual. The screen shot is zoomed in fairly tight, too.
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  8. #8
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    Looks like drift from the barometric pressure changes affecting the barometric altimeter to me. What is the time difference between the tracks? And the speed as @shiggy suggests. The left track is faster with fewer points.
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  9. #9
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    - I've used a Garmin 450 rather than one of their bike-specific units and it doesn't differ THAT much; that does seem to be a bit dramatic........of course, that said, I do bit of editing with the Garmin mapping software, and I usually only use the uphill data since I was moving MUCH slower so the unit mapped the ride better.........
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