Health App Step Length

I realize this is an old post--about 2 years old--but I thought I'd revive it. As others have pointed out, it cannot possibly be true that IOS/iPhone uses GPS for distance. Over the last month I've taken several walks with my wife. We both have iPhone 6s, bought at the same time. She consistently records 10-20% more miles than I do.

To call this question "solved" is simply wrong. This issue remains unsettled.

Jim

The Apple health app in nothing more than a toy and using it to measure activity is a huge waste of time. On 8/27/2017 my wife and I went on several walking tours in Washington D.C. We were never more than 30 feet apart the entire day and her phone (both are iPhone 6+) registered more than 7.5 miles walked and mine registered 5.1. . There was also a large discrepancy in stairs climbed. I understand that there is a difference in the length of our strides but supposedly the app uses GPS for calculating distance. If that's true then this app is woefully broken and just a flashy, useless bauble.

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.

Like many of you, I've become skeptical about the accuracy of the walking/stairs part of the Health app. Like many, I've 'tested' it in various ways, most recently check to see how many steps it gave me at dance class. As you can guess, even after a pretty steady hour of dancing, since it was- from the point of view of the Health app - in one place, hardly any steps had recorded. Similarly, if I walk about the small oval track at the gym, it records relatively few steps, whereas if I go for a similar timed walk in more or less a straight line, it records many more steps.

At best, it's a reminded to "walk more", and does give you a very rough idea of how much activity you do relative to other days.

What would it take for Apple to improve it?

Hal

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.

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.

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

"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

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!

James C Austin wrote:

As others have pointed out, it cannot possibly be true that IOS/iPhone uses GPS for distance.

Yes, it's true.

To call this question "solved" is simply wrong. This issue remains unsettled.

The original poster gets to mark the thread as "Solved". I'd suggest you start a new thread and describe your particular issue. You'll get more attention to it that way. Explain what's happening and what troubleshooting steps you've already taken.

Best of luck.

If the Health app is using gps to determine distance, it is doing a very bad job. I have tested this several times, and this morning is typical. The app said I walked 1.5 miles, but if I use the Google Earth path tool, I get 1.93 miles, which I believe, given that I use GE professionally and have double-checked it accuracy. The difference represents an error of about 22%.

"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

Settings/Privacy - Location Services.

Thanks

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

Hal

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