Workout app and MapMyRun Distances Are Inconsistent

Hi law826,

I'm sorry to see your Apple Watch is not reporting the distance correctly. To help resolve this issue, I recommend going through the calibration steps which are outlined below.

Calibrating your Apple Watch for improved Workout and Activity accuracy - Apple Support

Have a great weekend,

Alex H.

I didnt say trust AW over runkeeper, only that there are many variables that you should look at to ensure your perception of accuracy is correct.

And just my two cents but the AW should be thought of like a fitbit or any other device that is measuring distances based on steps (and ones doing so via your wrist). They are never going to be as accurate as GPS-based devices (ie a garmin watch or iPhone app using GPS). Until Apple either puts a GPS in the watch or decides that it will use actual GPS data from phone to measure distances when selected, you should not expect similar accuracy (although, i am not 100% on what is actually going on since the language is a bit ambiguous -- see below). Bottom line is that if you need distance accuracy down to the hundredth or even 10th of a mile, shouldnt be using the AW over something like runkeeper if both are readily available.

Calibrating your Apple Watch for improved Workout and Activity accuracy - Apple Support

Same here. Just took my watch (with phone) for first time for run this morning. Had previously used a Garmin watch. Ran the same course/path that consistently was always 7.0 miles on the Garmin (and verified mapping on my computer the path in Google maps). This morning, I set watch for 7.0 mile goal to run same path. Had to actually run 7.75 (according to Garmin watch my daughter was wearing while with me) to get to 7 miles. Wish I could see a visual map of where the phone/watch THOUGHT I was. So far, not happy. I know it's not the watch. It's the phone since that's where the GPS is coming from. Wonder if I need to return my phone. (6+)?

Must be a software thing with the app on the phone. I used MapMyFitness today and got accurate results. GPS is feeding from same phone. Health app showed much lower mileage than MapMyFitness. Weird, but it seems apparent that Apple is using a different algorithm to error correct (if it uses any) the mileage/distance. Seems weird that a 3rd Party app gets it right on the same equipment.

My problem may have been I was trying to get accurate GPS readings in a very hilly and tree covered area. i guess the GPS receiver in my Garmin watch is more sophisticated than the iPhone's because it didn't have the accuracy issues in the same environment.

But, I followed the instructions this morning and ran with Apple Watch and iPhone on flat track today for 20+ minutes To calibrate. 30 minute walk then a 20 minute run. Distance was accurate in both. So, I'm happy now. Have to accept that the phone isn't a dedicated GPS unit and has its limitation.

Still dont know why another app (MapMyRun) can be accurate in the hilly area with the trees on the same exact piece of hardware. Has to be a software algorithm.

Cause watch isn't using GPS to calculate your distance. Its using GPS to help the accelerometer better hone your stride length (as part of steps calc) and calculate distance covered this way. Given most of us our not professional runners, my guess is stride length varies run to run so I would guess it probably takes more like 3-5 runs to have a good approximation of your stride length at various speeds. But in the end, it will be step-based distance, not GPS based distance.

FWIW, my first outdoor run and walk were off by about 15% from what Runkeeper/Runmeter told me. After two additional runs and a handful of walks, from my last outdoor run in NYC park (so elevation changes and not best location for GPS):

RK: 4.31 miles

RM: 4.29 miles

AW: 4.20 miles

Seems to be getting closer and closer. Be interested to see how close it gets after 10+ runs. But bigger test would be running without the phone. Perhaps I will try that same route again this way to see.

I had the same issue on 2 different watches (1 Apple Watch Sport, 1 Apple Watch) using 2 different iPhones (5s and 6).

What I saw after several tests is that if I carry my iPhone with me and the iPhone sits in a waist belt (usually in a horizontal position) either in front or in the back of your body, the Workout app would come out around 20% short with the Outdoor Runing profile.

However if I carry the iPhone in my Hand or in an arm pocket on the same arm as the watch (in vertical position), the distance would be measured correctly and very precise.

Can anyone try and confirm this? Where do you carry your iPhone during your outdoor running workouts and is it carried horizontally or vertically?

Maybe we can further narrow this down if others can reproduce this as well.

By the way, the calibration process did not help with this at all. The watch correctly measures distance while walking or cycling as well, it's just running with the iPhone in horizontal position around the waist where the Workout app is completely wrong about the distance.

That could well be it. Im also using a waist belt and always had problems with the distance. Im using the watch on its own without the phone since a week for my runs. Its somewhat accurate then. I guess I will have to try out an arm pocket. But if thats the actual problem, its still a bug that has to be fixed.

Just before I saw your post, I had figured this out. What I equated to being running on a flat open surface as being the solution to the inaccuracies, it actually was where/how I carried my iPhone. Just happened that when I tried it out on an open track and got the most accurate (to the meter) results I was hand carrying my phone in a vertical position. Did both a walk and run (separately) and each were very accurate.

The next day, I went running back to my regular route and again I was off 10-20%. Difference? I had my phone in a waist pack horizontal against the small of my back. Was about to take back the watch/phone to see if phone was a problem when I tried halfway through the run to stop and start a new run with my phone in hand. Guess what? Back to spot-on accuracy for the run.

So, looks like you're on to something. Seems weird that the phone has to be in some certain orientation to receive GPS signals accurately but at least I found I could get accurate results.

Obviously, this thing is not going to be as good at distance accuracy as a dedicated GPS fitness watch which is designed specifically for that. Although, I have to believe a 2nd or 3rd generation Apple Watch will have its own GPS. Oh, the downside of being an early adopter. BUT, I still love my watch. Overall, it is an amazing piece of technology just disappointing in this area right now.

I always used Map my Run when walking/jogging and bike riding. Have been using the Workout App since getting the Watch but threads like these made me want to test them against each other.

Well unfortunately i started the Workout App and forgot to start May My Run. I did start it and after finishing my walk, I deducted the begining amount from the Workout total (3.35 - 1.58 miles) 1.77 and compared it to Map My Run (1.80). Not exact but pretty close for my purposes.

The phone receives GPS signals just fine in a horizontal orientation. I use it all the time with the RunKeeper app, and it's quite accurate. But it sounds like maybe this messes up the way the info is interpreted by the Apple Watch? Weird. For what it's worth, I always have my phone horizontal in a waist pack for my runs, and I'm having the same problem as others with 10-20% of my distance getting dropped (even though RunKeeper on the iPhone is tracking everything accurately at the same time).

I don't think that it is a GPS issue, otherwise all the other running apps would have wrong data as well.

My assumption is, the phone motion sensor is somehow being used by the watch or compared to the watch motion sensor. Keeping the phone either horizontally or close to your body on the waist is probably messing with this process, therefore causing issues with the distance tracking. May even be related to that calibration service running on the phone (in location services). Maybe it's worth turning the service off and giving it another try - will test that next time.

Workout app is not using (or so how I interpret Apples language) GPS to calculate data as I mentioned. Its just using it as a data point to refine your stride length which in turn helps better approximate your distance. So they are not using the same data. As someone pointed out, perhaps on outdoor cycling, it is using GPS since the accelerometer would not be very useful.

I will say that Runkeeper should not be viewed as an official source of GPS data and thus being accurate. I have done 5 tests using Runkeeper, Runmeter, and AW compared against the actual mileage of my tracks using the Footpath app. Whats nice about Footpath compared to Google Maps is that you can draw your paths without having to be straight lines. So if you know that you crossed on a diagonal, you can map it a bit more accurately. I am in NYC and so what problem with GPS is that its harder to get a consistent signal because it bounced off building and or tree cover. I could show you the maps but basically you can observe these problems (which are also related to the GPS capabilities of the iPhone) in how the maps for both RK and RM show me crossing the street or doubling back when in fact i ran in a straight line up one of the avenues. Or on a park run, you can see the GPS jump to the wrong trail for a small portion. In total, these small inconsistencies can add up to a material difference; however other times, the impact is not as great and I will get readings within 0.02 for all three when compared against Footpath.

From my experience so far, I have amassed 9 runs and 15 walks with the watch all using the workout app and the phone. My last 5 activities have been very very close to the Footpath distance whereas the first 5, on avg were off by 0.4. These are all across very similar routes, with 2 outliers when i traveled. I am now about to test how these compare when no phone is being used, more for intellectual curiosity as in reality, i almost always carry my phone with me.

Okay but when you're running on very well-defined running trails with no deviation from the path, and RunKeeper agrees with the trail distance but the Workout app is off by 10% or more, I'd trust RunKeeper over the Workout app. Similarly, when I run in an officially-measured race and RunKeeper agrees with the distance & pace, but Workout doesn't, I'd say there's an issue with the Workout app.

I get what you're saying about Workout using GPS as an additional data point to calculate distance (combined with accelerometer data) rather than as the absolute truth, but if that causes it to underestimate distances so much, then I'd consider that a major defect in the algorithm.