Pacer vs MapMyRun
December 5, 2015 9:31 PM Subscribe
Just started doing long walks and tracking them on my iPhone 4. Pacer says I have done 5744 steps and 3.8km but MapMyRun says I've done 5.11km and 7054 steps. I've had them both open the same amount of time.
How do I work out which app is right?
You could map one of your walks out manually here, and see which app comes closer to that distance.
If you can zoom in on the tracks in each app, you might find that one of them has a lot more zigs and zags between waypoints than the path you actually walked, making the total higher than it should be, or one of them lost its GPS connection somewhere along the way and then just calculated a straight line when it reconnected, making the total lower than it should be. That's been my experience when I've seen large variances like that between apps or devices.
posted by mammoth at 10:23 PM on December 5, 2015
If you can zoom in on the tracks in each app, you might find that one of them has a lot more zigs and zags between waypoints than the path you actually walked, making the total higher than it should be, or one of them lost its GPS connection somewhere along the way and then just calculated a straight line when it reconnected, making the total lower than it should be. That's been my experience when I've seen large variances like that between apps or devices.
posted by mammoth at 10:23 PM on December 5, 2015
Neither app will be accurate. The accelerometers in phones are lousy for accurately counting steps.
The question is "What do you need accuracy for?"
If you merely want to track your exercise level inaccuracy is likely to be a small issue. Just take it is as ordinal data (ie - did I move more or less than a the day before and discount the amount).
If you want to use the data for some other purpose - ie - inputting into calorie counting systems for diet purposes - get more accurate measures like GPS tracking with Runtracker or Endomondo and time your actual exercise sessions by pushing start and stop.
If you want to calculate your baseline non-deliberate-exercise movement I'd suggest getting dedicated pedometer but I don't think it is all that valuable for calorie counting purposes - just chosing the sedentary baseline and tracking all sustained walking that lasted more than 5 minutes was enough for me to get 95% accurate calorie burn tracking when I was counting.
posted by srboisvert at 6:44 AM on December 6, 2015
The question is "What do you need accuracy for?"
If you merely want to track your exercise level inaccuracy is likely to be a small issue. Just take it is as ordinal data (ie - did I move more or less than a the day before and discount the amount).
If you want to use the data for some other purpose - ie - inputting into calorie counting systems for diet purposes - get more accurate measures like GPS tracking with Runtracker or Endomondo and time your actual exercise sessions by pushing start and stop.
If you want to calculate your baseline non-deliberate-exercise movement I'd suggest getting dedicated pedometer but I don't think it is all that valuable for calorie counting purposes - just chosing the sedentary baseline and tracking all sustained walking that lasted more than 5 minutes was enough for me to get 95% accurate calorie burn tracking when I was counting.
posted by srboisvert at 6:44 AM on December 6, 2015
As a data point, I find that MapMyHike, shows I've covered longer distances than anything in the trail guides, or signs along the trail say.
posted by humboldt32 at 9:09 AM on December 6, 2015
posted by humboldt32 at 9:09 AM on December 6, 2015
More important than absolute accuracy is consistent measurement, so that you can accurately see your progress over time. Try re-walking the same route multiple times and see which app gives you the most consistent answer.
posted by samthemander at 9:14 AM on December 6, 2015 [1 favorite]
posted by samthemander at 9:14 AM on December 6, 2015 [1 favorite]
An iPhone 4 is before Apple added dedicated step tracker hardware to the phone (which was in the iPhone 5S.) So I think each app had to do their own step calculation from the raw accelerometer data, and there is a lot of variability in that.
Given that, the phone does have a GPS sensor, so both apps should be able to use that to get much closer to each other than you observed. Unless one didn't use the GPS, and only used the steps to guess it, which is how basic step trackers work.
posted by smackfu at 6:57 AM on December 7, 2015
Given that, the phone does have a GPS sensor, so both apps should be able to use that to get much closer to each other than you observed. Unless one didn't use the GPS, and only used the steps to guess it, which is how basic step trackers work.
posted by smackfu at 6:57 AM on December 7, 2015
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posted by Night_owl at 9:41 PM on December 5, 2015 [1 favorite]