Workout distance awful!

MrMoonUK

macrumors member
Original poster
Jun 2, 2015
90
59
UK
i have clocked up over 2hours running with Apple watch so far and I am disappointed! Yes I have even dragged my iPhone 6 along for GPS. However it just isn't accurate!

Today:

Garmin Forerunner 620 7.02 miles

Apple Watch 6.85 miles

This is unacceptable! That distance difference is huge!

The garmin has proven accurate over IAAF measured courses, so I trust it.

How can Apple Watch get it so wrong when the iPhone is paired?
 

Andy in Embsay

macrumors member
Apr 20, 2015
81
0
I think it might be something to do with the algorithm they use, as Strava is pretty accurate on my phone, but the watch (and I only ever run with it with my phone with me) always, always measures shorter than my Garmin.
 

Julien

macrumors G4
Jun 30, 2007
11,140
3,829
Atlanta
i have clocked up over 2hours running with Apple watch so far and I am disappointed! Yes I have even dragged my iPhone 6 along for GPS. However it just isn't accurate!

Today:

Garmin Forerunner 620 7.02 miles

Apple Watch 6.85 miles

This is unacceptable! That distance difference is huge!

The garmin has proven accurate over IAAF measured courses, so I trust it.

How can Apple Watch get it so wrong when the iPhone is paired?
Huge? The difference from 7.02 to 6.85 is only 2.45%. This is hardly Huge. Consumer GPS devices are generally considered accurate if below a 3% error.


I also have a 620 and use both. For me the Garmin 620 is my official run recorder and my :apple:Watch is for over all fitness.

Until (or if) Apple switches to GPS mapping and not just accelerometer calibration, distance measurements will always be in flux unless you keep a steady cadence and stride length. It is just the nature of accelerometer measuring.
 

iPhysicist

macrumors 65816
Nov 9, 2009
1,314
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Dresden
I have my watch calibrated the way apple advised to do and its accuracy is stunning! I did a run without my iPhone on a 2km lap and after 3 laps my watch gave me a distance of 6.08km.

The trick is to do the calibrating (and don't use other GPS Apps during that procedure). My first calibration was awful too because I mapped my runs with Nike running (but I don't know for sure that thats the culprit) . I unpaired the watch and re-paired it. Then did four 6km runs with 6- ,5- ,4:30- , 5-Minutes per km and from this point I had a pretty accurate reading across all my runs even running up and downhill.

Give it a try and do the calibration again.

Don't forget that the GPS signal is not THAT accurate. You can easily be of 10m and that adds to the whole.
 

Newtons Apple

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Mar 12, 2014
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Jacksonville, Florida
From what I understand the iPhone GPS on calibrates the watch and it does not use the GPS for accuracy. This is something that needs to change. The difference in the distances the OP saw are not that bad and not the end of the world!
 

JSB1540

macrumors 6502
Apr 24, 2015
497
194
How anyone can say the distance difference is "not that bad" is beyond me it's quarter of a mile!!! That's huge!
I am only doing brisk walks, but after several times carrying the phone it is spot on. I have measured from milepost to milepost, so unless the DOT is wrong, mine is giving accurate measures.
 

MH01

Suspended
Feb 11, 2008
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Huge? The difference from 7.02 to 6.85 is only 2.45%. This is hardly Huge. Consumer GPS devices are generally considered accurate if below a 3% error.


I also have a 620 and use both. For me the Garmin 620 is my official run recorder and my :apple:Watch is for over all fitness.

Until (or if) Apple switches to GPS mapping and not just accelerometer calibration, distance measurements will always be in flux unless you keep a steady cadence and stride length. It is just the nature of accelerometer measuring.
Have you got a source hat States that's consumer devices within 3% are accurate. 3% can be quite a large number depending on the distance in question
 

JSB1540

macrumors 6502
Apr 24, 2015
497
194
i have clocked up over 2hours running with Apple watch so far and I am disappointed! Yes I have even dragged my iPhone 6 along for GPS. However it just isn't accurate!

Today:

Garmin Forerunner 620 7.02 miles

Apple Watch 6.85 miles

This is unacceptable! That distance difference is huge!

The garmin has proven accurate over IAAF measured courses, so I trust it.

How can Apple Watch get it so wrong when the iPhone is paired?
How many times have you calibrated? You just recieved it on Wednesday, correct?
 

Julien

macrumors G4
Jun 30, 2007
11,140
3,829
Atlanta
Have you got a source hat States that's consumer devices within 3% are accurate. 3% can be quite a large number depending on the distance in question
While my comment was made without consulting any sources here is a test of 12 GPS devices with a combined average error rate of 2%. If you look at the table you must add 0.6% to the error rates because the tester misidentified the test track a ¼ mile when it is 400M (see last paragraph) .

http://www.singletracks.com/blog/gps/gps-distance-accuracy-test-smartphone-apps-vs-dedicated-gps/
 

mac.cali

macrumors 65816
Mar 16, 2012
1,347
245
I have my watch calibrated the way apple advised to do and its accuracy is stunning! I did a run without my iPhone on a 2km lap and after 3 laps my watch gave me a distance of 6.08km.

The trick is to do the calibrating (and don't use other GPS Apps during that procedure). My first calibration was awful too because I mapped my runs with Nike running (but I don't know for sure that thats the culprit) . I unpaired the watch and re-paired it. Then did four 6km runs with 6- ,5- ,4:30- , 5-Minutes per km and from this point I had a pretty accurate reading across all my runs even running up and downhill.

Give it a try and do the calibration again.

Don't forget that the GPS signal is not THAT accurate. You can easily be of 10m and that adds to the whole.
How did you calibrate it?
 

exxxviii

macrumors 65816
May 20, 2015
1,423
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In my experience of having run nearly 7,000 miles with different GPS watches, I find them very accurate. Lots of theorists will quote 2% accuracy, etc., but in practice, they have been more accurate than that for me.

For a runner, a tenth of a mile is a big deal. I run races with friends who have a variety of GPS watches. We usually finish within a few hundredths of a mile of one another after a half marathon. We are all slightly higher than then official distance, but we chalk that up to not having run the shortest measured line. On my daily 5 mile run, three different watches measure within one or two hundredths of a mile difference. So, in real life, I would say that my GPS watch has <<1% error.

My iPhone with Runkeeper is typically one or two tenths of a mile off from my GPS watch. I always chalked that up to either the iPhone or Runkeeper's problems. The iPhone only occasionally matches the watch, so I only trust my watch. My gut is that the AW's accuracy is subject to the accuracy of the phone.

I have only run with my AW twice so far, and both times with the phone. I am not so worried about accuracy yet. I plan to give it about 50 miles with the iphone for lots of calibration before I run without the iPhone to see how it does.
 
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MH01

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riverfreak

macrumors 65816
Jan 10, 2005
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Thonglor, Bangkok
i have clocked up over 2hours running with Apple watch so far and I am disappointed! Yes I have even dragged my iPhone 6 along for GPS. However it just isn't accurate!

Today:

Garmin Forerunner 620 7.02 miles

Apple Watch 6.85 miles

This is unacceptable! That distance difference is huge!

The garmin has proven accurate over IAAF measured courses, so I trust it.

How can Apple Watch get it so wrong when the iPhone is paired?
Wow!

n of 1

For everyone touting the accuracy of GPS what latitude do you live at? Do you live in a mountainous region or area of constrained skyscrapers? Surely SURELY you've seen moments where the precision of location has dropped off.

It doesn't take too many of those events to wildly change, say, a linear distance measurement over the course of 5k.

It's incredibly accurate. But it's precision varies.
 

exxxviii

macrumors 65816
May 20, 2015
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552
Wow! n of 1
Are you building an airfield and using the Apple watch for a tape measure?
Posts from non-runners who may never have seen the accuracy of a Garmin, Timex, or Tom-tom running watch. (Just supporting the OP.)
Well newbie, as others have posted, if you haven't done the calibration then what do you expect?
He probably did. Apple says it only takes 20 minutes to calibrate. The OP probably has 6x the calibration time.
 
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JSB1540

macrumors 6502
Apr 24, 2015
497
194
It takes 20 minutes each time it calibrates, (even non-runners understand this) more individual times the better. Apple instructions: "And, whenever you use Apple Watch and iPhone to walk or run outside in the Workout app, it will continue to calibrate the accelerometer by learning your unique stride length at different speeds, and get more accurate over time."
 

PilotC150

macrumors regular
Apr 24, 2015
124
220
I've been doing runs three to four times a week since I got my watch (anywhere between 3 and 10 miles), and always running with my iPhone. I record the workouts with the Watch's Workout app and with MapMyRun.

On Saturday I did a run that was supposed to be five miles. I really wanted the Workout app to record 5 miles, so I kept going until it hit 5 miles. MapMyRun, at that point, recorded 5.27 miles. That's over 5% difference and that really is unacceptable, considering both apps are using the same GPS data. I really wish I could see the GPS data the phone is using to calculate distance so I could see where it's smoothing out the curve and losing distance.

This is a common theme with all of my runs. The Workout app always records a shorter distance than MapMyRun.
 

foxkoneko

macrumors 6502
Sep 5, 2011
379
139
less than a 3% difference. The garmin isn't 100% accurate either (obviously). There'll always be some small difference.
 

acctman

macrumors 65816
Oct 26, 2012
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692
Georgia
i have clocked up over 2hours running with Apple watch so far and I am disappointed! Yes I have even dragged my iPhone 6 along for GPS. However it just isn't accurate!

Today:

Garmin Forerunner 620 7.02 miles

Apple Watch 6.85 miles

This is unacceptable! That distance difference is huge!

The garmin has proven accurate over IAAF measured courses, so I trust it.

How can Apple Watch get it so wrong when the iPhone is paired?
why do you assume that the Garmin is 100% accurate over the AW? From what I see on Garmin fitness watch test (on the net) there is a 2-3% error that the garmin has when tracking.
 

MrMoonUK

macrumors member
Original poster
Jun 2, 2015
90
59
UK
Errr I have calibrated it, it's racked up over two hours tethered to the I phone!


Oh and garmin has proven accurate to with about 0.02 of a mile on IAAF measures courses that's a hell of a lot better than Apple watch.

People need to stop defending the watch, until it uses actual GPS and not the accelerometer it will be rubbish for running
 
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Mobster1983

macrumors 6502a
Sep 8, 2011
626
446
My main problem is lots of my runs/walks I do with my dogs. Two of them. That means a leash in one hand. So basically the Apple Watch is completely useless because it doesn't use the GPS from the phone. There is no reason whatsoever the workout app should not use GPS from the phone as its primary method of measurement, and use pace count as secondary.

My last run/walk logged 1.28 miles on MapMyRun, and 1.10 on my Apple Watch. That is a 16% difference and is absolutely horrible on Apple's part. I'm very disappointed with this, and so unfortunately need to use two watches when running, my Apple Watch and my Garvin Forerunner, which has ALWAYS been right on the money for me.
 
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