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# Question:Q:Health App Step Length

I am curious as to what a 'step' length is within the iphone Health app logic. The app registers steps and miles. Is a step 12 inches? So if my stride is 2.5 feet and the iphone logs that I have walked 1746 steps, have I gone 1746 feet or some factor of the iphone 'step length'? i.e.: if iphone has a step at 2.5 feet, I would have actually walked 4365 feet. ??????? How can I trust the 'miles' on my dashboard?

iPhone 6 Plus, iOS 8.1

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The iPhone measures both steps and distance separately. It measures distance using GPS functionality and steps using the accelerometer. So it doesn't need to know step length to find distance. It DOES know it, however; under Location Services there is a function called "Motion Calibration." That's what its for.

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My husband and I each have an iPhone 6Plus. This morning we took the exact same hike together and got very different results for both steps and distance run/walked. I understand the difference in steps, but if GPS is used for distance why would we get results that differ by more than a couple miles?

My wife and I also went walking today. We walked on a flat path with measured quarter-miles. We also counted steps for a bit (200 each). We each have an iPhone in a tight front pocket, and I don't believe in that "extra-jostle" theory. It overcounted one of us and undercounted the other by enough (about 30-40%) that the results were meaningless. We also checked the miles. We first did it for 1/2 mile - mine was exact, wifes's was about 25% off. Over two miles, both were off, mine by 35%. Bottom line - it seems to be so unreliable and inconsistent that it has no value, other than as a toy. I will continue to test, perhaps holding both phones in same pocket. And it shouldn't need calibration if it uses GPS for miles and accelerometer for strides.

MY husband (6 ft) and I (5 ft) hike frequently. Yesterday we had a discrepancy of over 2,200 steps and 5 flights between the 2 of us. I could understand if I got more steps than him since my stride is shorter but he is always getting more steps.

what is going on?

MY husband's and my steps are always different as well, even when we've been to the same places. Today mine was 14k steps and his was 22k. We'd been together all day.

I'm somewhat skeptical that Health app is using GPS for distance, because Health app's distance reporting continues to function when one is walking or running on a treadmill.

Unless you jog slowly or walk fast, there will be a speed difference, but all it will report is steps, unless you use one of the hundreds of apps that let you tell it what you are doing (or the Workout app on the Apple Watch). A car on a rough road rarely goes under 10 MPH, and unless the road is rough for miles, it won't have much of an impact on the step count. I've never tried driving for miles on a rough road, so I don't know how much inaccuracy it would introduce.

FOLLOWUP: I just drove for 1:10 over some very rough roads in Manhattan that had been milled for repaving. My phone showed no steps during that 70 minute interval.

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Question marked as Solved

The iPhone measures both steps and distance separately. It measures distance using GPS functionality and steps using the accelerometer. So it doesn't need to know step length to find distance. It DOES know it, however; under Location Services there is a function called "Motion Calibration." That's what its for.

Mar 5, 2015 11:20 AM

"The iPhone measures both steps and distance separately. It measures distance using GPS functionality and steps using the accelerometer. So it doesn't need to know step length to find distance. It DOES know it, however; under Location Services there is a function called "Motion Calibration." That's what its for."

Where are 'location services' located?

thanks

Hal

Jun 4, 2015 8:19 AM

Thanks, but that doesn't allow any adjustment. :-(

The reason for my question is that the number of steps Health records and the miles it shows don't work out to be the same. Siri says a miles is 4224 steps, but when I do the arithmetic with the steps' miles the Health app gives me, they are significantly different.

If I understood the explanation earlier, the Phone is using GPS data to measure distance, and some sort of counter to measure steps? Is that right? Also, how does it measure Stairs -- I've deliberately gone up and down the stairs at the gym, counting the number of times I do it, and my actually count and the Health apps count are seldom the same.

At best the Health apps seems to give a rough idea of how much activity, e.g., steps/miles walked, stairs climbed, etc.

Am I wrong?

Hal

Jun 4, 2015 8:32 AM

For most people a mile is between 2000 and 2100 steps. (Average step length is 31 inches; 1 mile = 5280 feet or 63,360 inches; dividing this by 31 inches gives 2044 steps.) Siri does not use data on the phone; it does an Internet search, and found a rather bizarre result from Wolfram Alpha (I was able to duplicate that result; need to email Stephen Wolfram, I guess). The phone uses the accelerometer to measure steps, the same way any pedometer does. The accuracy of the count is affected by how you carry your phone. If you carry it in a pocket where it can bounce around it will overcount, as each jostle will count as a step. If you wear it in a belt holster it will be much more accurate. It counts steps by detecting vertical motion, and it assumes that a flight of steps is 17 steps (an average based on home construction standards) and that the steps are standard height.

Jun 4, 2015 8:48 AM

Thanks

i knew Siri did an Internet search, but I didn't check further. Her "sources" are usually pretty good! :-)

Hal

Jun 4, 2015 9:49 AM

"The iPhone measures both steps and distance separately. It measures distance using GPS functionality and steps using the accelerometer."

If Health measures distance using the GPS, how does it know whether you are walking or jogging ... or in a car on a rough road? I'm not try to be a smart alec, I'd really like to know.

Hal

Jun 5, 2015 8:07 AM

Unless you jog slowly or walk fast, there will be a speed difference, but all it will report is steps, unless you use one of the hundreds of apps that let you tell it what you are doing (or the Workout app on the Apple Watch). A car on a rough road rarely goes under 10 MPH, and unless the road is rough for miles, it won't have much of an impact on the step count. I've never tried driving for miles on a rough road, so I don't know how much inaccuracy it would introduce.

FOLLOWUP: I just drove for 1:10 over some very rough roads in Manhattan that had been milled for repaving. My phone showed no steps during that 70 minute interval.

Jun 5, 2015 2:33 PM

HI,

I really appreciate your responses. It's been most helpful in understanding how the Health app works. Taking a drive on a 'rough' road meant going" above and beyond"! Thanks!

Hal

PS: I tried to mark your last post as 'helpful', but for some reason it wouldn't take. But, as I said above, it was very helpful!

Jun 6, 2015 4:59 AM

Halle wrote:

HI,

I really appreciate your responses. It's been most helpful in understanding how the Health app works. Taking a drive on a 'rough' road meant going" above and beyond"! Thanks!

Hal

PS: I tried to mark your last post as 'helpful', but for some reason it wouldn't take. But, as I said above, it was very helpful!

Well, I had to get somewhere, and Manhattan is in the process of repaving the streets in the West 40's blocks. So it wasn't like I had a choice, going from the Intrepid to the Central Park Zoo 😉

Jun 6, 2015 6:49 AM

Interesting to note that steps does not enter into the calculation of distance. I expected that it did. Nice to know that and not expect

more from it than just a count of steps. BTW, Dashboard consistently computes my distance traveled as greater than the distance

that the MapMyTracks app does. I understand how extra jiggling can cause extra steps, but both apps supposedly use GPS. Maybe

the app needs further 'tuning'?

Jun 16, 2015 7:21 PM

MY husband (6 ft) and I (5 ft) hike frequently. Yesterday we had a discrepancy of over 2,200 steps and 5 flights between the 2 of us. I could understand if I got more steps than him since my stride is shorter but he is always getting more steps.

what is going on?

Jul 6, 2015 12:03 PM

Yes, I Am FrencH! But the problem is shared. Try taking the Métro in Paris and you will see how quickly the Health App (Santé) records distance and steps...while you are standing still. Kinde of useless...

Jul 21, 2015 12:17 PM

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Question: Health App Step Length