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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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Old 08-16-16, 02:12 PM   #10
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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.
Wife and I do this all the time... using MMW... she has an iphone and I have android... we have never had the same miles for the same walk. Usually my phone shows a bit more.

I just went on a deep forest walk with a friend... she had an iphone and MMW... her phone tracked the routed pretty well, my phone choked and showed 1 mile of our over 2 mile walk... it did some straight lines that obviously left the trail. It logged the time right, but blew the track.
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Old 08-16-16, 02:15 PM   #11
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BTW I once did a comparison over 30 miles between my bike comp... which is NOT GPS, and another rider's Garmin bike comp... there was a .2 mile difference. I figured I was calibrated well enough. We could have had that variation just in the way we swerved.
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Old 08-17-16, 07:09 AM   #12
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I am using Runtastic, MapMyRide and Strava on my two phones and I run two app at the same time just for fun. Runtastic wins as it has heart heart info for free and it also audio announce heart rate zone change. It has auto pause. They are all pretty close in the stats, except for calories burned. It varied widely!

I use to have a phone (Note 4) where I would loose the GPS signal under trees.

I now have the Note 5 and S7 and they both have great GPS signal. No endorsement on Samsung. LOL. Thats one of the reason why those phones have glass back (GPS?) and 4 wireless charging.

One way to test is get an app "GPS Test" and I get 3D lock signal inside building. That means you have great GPS sensitivity. Did you do this test?

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Old 08-17-16, 10:16 AM   #13
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Zombie thread.
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Old 08-17-16, 11:42 AM   #14
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I mount my phone using on the crossbar and have used mmr and icardio app and generally get about the same distance for a route that I ride a lot. I think the variance that I get is that I do not ride the exact same distance as I am riding on different parts of the road from one ride to another, shouder one time more in the center the next etc.
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Old 08-17-16, 12:10 PM   #15
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Zombie thread.
Also known as a necro-post
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Old 08-17-16, 11:36 PM   #16
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Zombie thread.
Maybe so, but I've been thinking about this since I bought a smartphone and started using GPS + apps.

I have a Cateye bike computer which I'll assume is the more accurate compared to GPS. For comparison, I've used both Strava and MapMyRide. By far, MMR is the more accurate, slightly more so in distance, and very much so in time. Strava's auto-pause is very unreliable for some reason. After a 1hr30min or so ride, MMR might be off time-wise by 30secs or so while Strava is off by as much as 2-3 minutes. The mileage is generally accurate to within .2-.3 tenths, which over a 20-25 mile ride I don't consider too poor.
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