How accurate are GPS apps for measuring distance?

  • suedeheadscot

    Posts: 1130

    Jul 09, 2011 8:00 PM GMT
    I use Adidas mi-coach. A friend has used something else and we've found that to measure distances that are shorter. I find Adidas mi-coach seems to measure the distances greater than runfinder.co.uk (which doesn't take into account the curvature of the earth).

    Sorry if this is a boring thread (shall we talk cock instead?) but if anyone can comment on this, it would help satisfy my curiousity!

    Cheers guys!

    Ewan
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    Jul 09, 2011 10:24 PM GMT
    The Adidas mi-coach has an app?

    I acutally had the mi-coach and it sucked. at least in my opinion. It was never right.
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    Jul 10, 2011 12:56 AM GMT
    I use iMapMyRun - seems to be okay in terms of measuring distance accurately. I typically run within the Central Park Loop. The "official" distance of the entire loop is 6.0273 miles (at least according to NY Road Runners, http://www.nyrr.org/resources/training/central_park.asp).

    Last time I ran the full loop and tracked it via iMapMyRun, the distance came in at 6.01 miles. Not too shabby!

    imapmyruncp.jpg
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    Jul 10, 2011 1:34 AM GMT
    This morning at the race a bunch of people were talking about how the course was off a bit on 5K and the 2 mile was too long. I asked how did they know. They all said they used their Garmin to determine that.
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    Jul 10, 2011 7:21 AM GMT
    I run with endomondo on my droid and a garmin. Endo is always off by sometimes as much as a half mile but i like that it tells me my times in my ear and friends on endo can type messages into the website which are read to you through your earbuds.

    When I ran Seattle Marathon the endo was off by over 1.5 miles by end of race. Garmin was within .1 miles of the official certified course.
  • samasaurusrex

    Posts: 84

    Jul 10, 2011 7:50 AM GMT
    Well... If grindr has taught us anything it's not to trust it. I never could find that guy standing 4 feet from my bed in my Chicago hotel room. Dang! Oh, you were asking about another app. Oh well.
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    Jul 10, 2011 8:07 AM GMT
    If they have a clear, solid lock, they are crazy accurate. My app is so accurate it knows when I have quit running when coming to intersections, and it knows it quick too. Granted, I am speaking about Android phones, specifically the Droid, Droid X, Droid 2, and Thunderbolt. Those all have solid GPS chips. I can almost guarantee any other modern phone will too, including other devices. Check out this pic of me biking around the dorms (note the blue dots...pausing at intersections):

    26477_1265991768810_1200240068_30632658_

    Long story short, it is accurate.
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    Jul 10, 2011 8:25 AM GMT
    Most GPS devices can grab your location within 50 feet.

    If you're going for a 5 mile run, the difference is negligible.
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    Sep 03, 2011 7:13 AM GMT
    Trocks797 saidIf they have a clear, solid lock, they are crazy accurate. My app is so accurate it knows when I have quit running when coming to intersections, and it knows it quick too. Granted, I am speaking about Android phones, specifically the Droid, Droid X, Droid 2, and Thunderbolt. Those all have solid GPS chips. I can almost guarantee any other modern phone will too, including other devices. Check out this pic of me biking around the dorms (note the blue dots...pausing at intersections):

    Long story short, it is accurate.


    I think I can shed some light on this.

    A wristwatch with a GPS receiver is at a disadvantage compared to an App running on a cellphone. The cell network electronics are still much bigger than a wristwatch. But the cell network can help you determine a fix quickly, especially if tall buildings prevent you from seeing more than one GPS bird.

    Verizon, UsCellular, and Sprint: regular voice/data signals are GPS-synchronized to enhance network capacity for the IS95 standard.

    Around 2007, that phone standard enhanced its ability to determine a fix if it can't see three GPS sat birds. AT&T/TMobile uses the European GSM system. They may have similar AGPS capabilities though.

    Anyway, wristwatch GPS, better than nothing. Cellphones sold in the US must have E911 enhanced location accuracy so they can find you in an emergency.
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    Oct 26, 2012 2:53 AM GMT
    Endomondo or any of those other apps are only as good as the smartphone, so using a high-end droid vs a basic model will show up with very different results.
  • Medjai

    Posts: 2671

    Oct 26, 2012 2:59 AM GMT
    I've always wondered this, since the accuracy of a GPS device is dictated by the available maps, and several laws. The US Military has veto on accuracy, and there are several limitations preventing civilian devices from overtaking the military on accuracy.

    However, by the looks of things, they are more than accurate enough for running use.