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Old 06-21-12, 11:14 AM   #1
jrickards
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GPS or MapMyRide app inaccuracies

I've been logging my rides with MapMyRide since last summer as well as using the mapping feature to plan out other fitness rides. This year, I have an Android phone and last week, downloaded the MapMyRide app. However, I've had a couple of issues with it but I don't know if they are related to GPS in general or the app.

The Auto Pause feature is nice since I like to know my time/speed on commutes independent of waits at intersections but twice in the last 6 days of using the app, the Auto Pause has not resumed: the first time, it missed about 3:30 at the beginning of my ride and today, it missed the whole of my 45 minute commute in to work. The other reason I enabled the feature is because I use long fingered gloves so I have to take off one glove to activate the app, then put the phone in the backpack, put the backpack on my back and get it settled, put my glove on, hop on the bike and then take off assuming that the Auto Pause will pause during all of that and then resume when I take off.

The other issue is that my ride home ranges from 16.45 to 16.99km according to the app but I can't imagine that I weave that much to add 540meters to my ride.

I'm not set on MapMyRide so if anyone has any suggestions for a better app, I'm willing to switch.
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Old 06-21-12, 12:27 PM   #2
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GPS is not super accurate, especially in areas with lots of trees or steep hills or tall buildings.
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Old 06-21-12, 01:04 PM   #3
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I have a Garmin 305 that adds as much as 800' elevation gain to my ride in cloudy conditions for the same ride on non cloudy days. I prefer the elevated numbers.

My son in law downloaded the Strava.com app and is pretty happy with it.
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Old 06-25-12, 08:59 PM   #4
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There is a trade off between sample frequency and battery life. That and GPS is subject to logging issues depending on when and how the auto pause routine is implemented.

Look at the map closely, and/or set up a separate map for the known distance.
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Old 06-25-12, 10:27 PM   #5
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This is really interesting because I use MMR all the time as well. But just tonight I went for a 2 mi run with my daughter and we both used MMR/MMF on our phones (different models, but both Androids). We started exactly the same time, same route, same everything -- but mine showed 2.04 miles while hers showed 2.65mi. That's a huge difference, in terms of percentage! About 1.25mi into it we realized the discrepancy and the gulf between ours just continued to grow as time/distance passed.
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Old 06-26-12, 07:38 AM   #6
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This is really interesting because I use MMR all the time as well. But just tonight I went for a 2 mi run with my daughter and we both used MMR/MMF on our phones (different models, but both Androids). We started exactly the same time, same route, same everything -- but mine showed 2.04 miles while hers showed 2.65mi. That's a huge difference, in terms of percentage! About 1.25mi into it we realized the discrepancy and the gulf between ours just continued to grow as time/distance passed.
Zoom in and look at the route closely on the map. It could be difference in GPS performance between the two phones or their GPS reception depending on where and how you carry them on your person. If yours is dropping a lot of points it'll show up a shorter.
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Old 06-27-12, 01:33 AM   #7
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I have not used Map My Rides, but last week I managed to put Android on a 2 year old windows HTC phone I got from a friend and tested both MyTracks and Strava. I found the GPS to be incredibly accurate as far as location—naturally not so much on elevation—probably down to a couple of yards. At one point I had to go around a chicane designed to slow down cyclists before a crossing, and it showed up clear as day when I moved about 8 feet over. It did show some wobblyiness in the path during a climb out of the river bottoms though. I believe the difference in GPS receivers matter quite a bit too. A car GPS is less accurate and relies a lot on locking your position to what road it thinks you are on.
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Old 06-27-12, 02:08 AM   #8
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Similar discrepancies with Endomondo vs my Planet Bike wired computer - prev ride 30 miles, 5.2% difference, last ride 19 miles -1% difference. I'm going to continue comparing the two. I like the way you compared the out vs back leg of your ride so will try that a couple times also.
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Old 06-27-12, 06:39 AM   #9
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Zoom in and look at the route closely on the map. It could be difference in GPS performance between the two phones or their GPS reception depending on where and how you carry them on your person. If yours is dropping a lot of points it'll show up a shorter.

Ah yes, my route showed a very straight line, but hers was really jagged and twisty on the exact same path when we were side-by-side the whole time. Wish her distance was the accurate one!
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