# GPS geeks - moving time?



## Wherewolf (Jan 17, 2004)

I come from a running background and there are no stops in running. So I like to keep moving when biking. Lately I've been irritated at the reporting of moving vs. stopped times from my Garmin 800. E.g. on my longest ride this summer the total time was nearly 12 hours, yet the unit recorded about 4 hours of stopped time! There was a lot of slow climbing so perhaps the unit thought I was stopped.

So yesterday I did some experimenting with my 705 and 800 on a ride. I stopped for less than three minutes to have a gel and I got off the bike a few very brief times to walk some technical sections. I put the 800 on auto pause at 0 mph. It beeped every time I stopped and immediately when I started. Below is the data from both units as well as the data run though Topofusion. The 800 is way off. Any suggestions as to what to try?


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## ghettocruiser (Jun 21, 2008)

In a related inquiry, I still don't get why the fields for "Time" "Moving Time" and "Elapsed Time" on Garmin connect can all be different. Should at least two of them be the same?

I measure only elapsed time on rides, which although simplest, makes them look demoralizingly slow.


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## BigLarry (Jul 30, 2004)

So the discrepency that concerns you is the stop time of 3:25 on the Edge 800 versus 2:37 on the Edge 705? 

Frankly, this difference is ony a few seconds that could be picked up any number of places. And how do you know which is the "right" number? Maybe it took you a few seconds to get off your bike, or before you turned on or off the GPS at the start or end of the ride, so the real stopped time is over 3 minutes?

As for small errors you see, maybe the two units do not have the same threshold speed for what is stopped. The GPS tracks could be sampling at different rates, so the Topofusion analysis sees one as having more stop time than the other between the points. If one GPS is less accurate, the random motion can look like movement on one unit. 

I usually see Time and Elapsed Time as identical. Also, the GPS "auto pause" doesn't have a lot of meaning for a GPS track, which records track points at a position and time. I guess the "pause" just means it stops recording? That might explain why Time and Elapsed Time are not identical for the Edge 800 track. 

Anyway, it's tough to figure out why the difference without seeing the actual data points. On an 8 hour ride, I commonly see different computers and web sites giving slightly different stopped times from 1:15 to 1:30 hours. Mostly, I think it's the threshold speed for movement, as well as other factors I mention above. 

As for the 4 hours of stopped time on your long ride. Since you were indeed covering distance during that supposed stopped time, I suspect maybe your speed was often under the speed threshold for stopped. Again, if I see the data maybe I can figure out more.


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## Wherewolf (Jan 17, 2004)

*Garmin Connect*



BigLarry said:


> So the discrepency that concerns you is the stop time of 3:25 on the Edge 800 versus 2:37 on the Edge 705?


The numbers you quote above are after running both through Topofusion. The numbers on the right are from Garmin Connect, which shows a much bigger difference. There is no way I stopped for the 17 minutes the 800 recorded for the ride yesterday. The 7 minutes recorded by the 705 seems about right.


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## Harold (Dec 23, 2003)

yeah, I'm going to agree that there's probably a bunch of small differences combining to create the difference in stopped time you see. first, it looks like the two receivers were started at slightly different times.

I would also hedge my bets that the auto pause for both units has slightly different cutoff speeds. I, for one, do not use auto pause. The 800 as reported by GC seems to think more of your time was spent stopped. Which suggests to me that it was probably thinking you were stopped at times you were just moving very slowly. I am a somewhat slow rider, and this is why I don't use auto pause.

Topofusion seems to ignore something that GC is reporting, because those values are very close together in TF.


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## BigLarry (Jul 30, 2004)

Wherewolf said:


> The numbers you quote above are after running both through Topofusion. The numbers on the right are from Garmin Connect, which shows a much bigger difference. There is no way I stopped for the 17 minutes the 800 recorded for the ride yesterday. The 7 minutes recorded by the 705 seems about right.


Thanks for clarifying what bothered you. I also see many other items very odd, such as the moving speed on the Topofusion results versus the Garmin Connect, with the average speed anywhere from 1.5 MPH to 6.8 MPH.

Yes, 17 minutes is big relative to 7 minutes. But compared to a 230 minute ride overall, it's only a small error in the statistics. Again, it could be any number of things, from the track point sampling rate to speed threshold at which the GPS considers you stopped. Maybe you can look for a setting for "stop speed", but Garmin Connect doesn't have much ability to set fundamental parameters like this. Maybe more (or less) track points will help? Do the two tracks have the same number of points?


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## Wherewolf (Jan 17, 2004)

*Auto pause*



NateHawk said:


> I would also hedge my bets that the auto pause for both units has slightly different cutoff speeds. I, for one, do not use auto pause. .


The 705 was not on auto pause. The 800 was on auto pause at 0 mph and it constantly beeped to let me know it was working. It seemed to be doing a great job. I tried auto pause on the 800 for this ride because all my previous riding was done without it and the stopped times were way off. Both units were started and stopped within seconds of each other.


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## slocaus (Jul 21, 2005)

> Garmin Connect provides three Time measurements on the Details page:
> 
> Time
> Time is the recording time reported by the device. For Fitness devices, this should equal the Time value reported on the device. For other devices, this should equal the amount of time elapsed from the actual Start and Finish time of an activity.
> ...


Again:
Garmin Connect - FAQ
*How are the Time measurements defined at Garmin Connect?*

Moving Time

"_Garmin Connect *calculates* Moving Time by removing the amount of time when the user is stopped. This is helpful for customers who upload activities with a Garmin device that either don't have AutoPause or have AutoPause turned off._ *For those who have AutoPause turned on or hit the Stop and Start button in the middle of an activity, the Moving Time should be very close or equal to Time.*"

Reading the entry about Moving Time, the 705 is calculated, and the 800 is recorded. I read the above to mean that the 800 data is likely more accurate, in spite of your feeling that it is way off.

There is always signal "drift". In weak signal, steep north slope, heavy oak forest, I can be going 25 mph and have the unit go into pause for several seconds. Stopping for a "nature break", I have laid the bike down and had the auto pause beep repeatedly. Each of those will be an inaccurate recording, since "moving" vs "stopped" is wrong due to signal drift.

There is also the differences in gain sensitivity between different devices o the same model, let alone different models. The chips in each unit are different. I suspect that you will not get a definitive answer as to which is the "most" correct. Even the same GPS over the same course will record differently due to drift every single time. I don't even want to get into the differences in barometric pressure day to day, or hour to hour. I have hundreds of tracks to prove that, since 2005. 

Looking at the TF data, I have to wonder about this setting:


> Units Tab - Configures units of distance and coordinates.
> 
> Min speed to be considered "moving": Moving time calculations are used in several places in the program. This threshold value controls how fast the GPS must be moving to be considered "moving."


There are some significant differences in speed and pace between the two in your graphics. My guess is that those are calculated from elapsed time only in TF, so that drops the calculations since it includes stopped time in the 705 with no auto pause, but not in the 800 with auto pause active. Even that, reading it and looking at the TF graphics, makes no sense. I searched the TF manual and forums, but could not find anything about how moving time is calculated. You might email Scott.

My best guess is differences in the two units. I'd test both with auto pause, and both without to see if you can find anything better.


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## BigLarry (Jul 30, 2004)

Good info, Slocaus. I was looking in Garmin's help files, but didn't search the FAQs. 

Still, Garmin Connect seems to calculate Moving time based on some sort of algorithm besides just Pause or AutoPause, which my GPS doesnt have, as on long rides I usually see stopped times on Garmin Connect that compare reasonably (within 30%) to what I see on my GPS screen, and my bike odometer from wheel movement.


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## Wherewolf (Jan 17, 2004)

*800 moving time revisited*

I've done a bit more experimenting with the moving time on the Garmin 800. Today I put it in "record every second" mode and recorded to the SD card in case the file got too big. I felt great today and I barely stopped. The moving time was right on what I expected, and just a few minutes different than Topofusion and the 705 over a 5 1/2 hour period. I forgot to check how much it drained the battery. I wonder if it will deplete the battery faster. The calories burned was three times higher on the 705.

http://connect.garmin.com:80/activity/embed/119990442


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## BigLarry (Jul 30, 2004)

Wherewolf said:


> I've done a bit more experimenting with the moving time on the Garmin 800. Today I put it in "record every second" mode and recorded to the SD card in case the file got too big. I felt great today and I barely stopped. The moving time was right on what I expected, and just a few minutes different than Topofusion and the 705 over a 5 1/2 hour period. I forgot to check how much it drained the battery. I wonder if it will deplete the battery faster. The calories burned was three times higher on the 705.


Aha! I was questioning the sample rates of the track, but never got an answer. Again, what's the overall number of track points compared to the 705? Any case, glad it looks like you've figured it out.

Yes, recording every second will increase the batterry drain a bit. Not sure how much - your GPS is working most all the time anyway. So it might not be too bad. There might also be a next lower setting that works too.

As to which value is correct on calorie burn - at your size, and your very high HR and the high average power output on your rides, I'd expect you to be burning as much as 700-900 Calories/hour on average. At a 3X difference, one of the devices is completely off.


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## scoutcat (Mar 30, 2008)

turn auto pause off and make sure you are using the cadence sensor and the problem will be solved. all you need to worry about then is your ave moving speed and moving time. autopause is terrible and garmin needs to improve this feature.


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## Wherewolf (Jan 17, 2004)

*No cadence sensor*



scoutcat said:


> turn auto pause off and make sure you are using the cadence sensor and the problem will be solved.


I do not have a cadence sensor, no would I want one for mountain biking.


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## Wherewolf (Jan 17, 2004)

*Track points*



BigLarry said:


> ... what's the overall number of track points compared to the 705?
> As to which value is correct on calorie burn - at your size....


800 = 20,260
705 = 4614
So I'm fat? 
I don't care about the calories. Just amazing how much difference between the two units.
I used to run and I like to keep my heart rate up continuously. Aside from being slower than most of the group, I don't care for group rides because there is way too much stopping. I don't want it to look like I take naps on my rides


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## Wherewolf (Jan 17, 2004)

*Eureka!*

Really made an effort to keep moving today. Garmin 800 on 1 second recording to SD card. File is only 316 kb. I read that the new fit file format is tiny compared to the old format and that is why you can now record for more than 4 hours on 1 second recording. No noticeable battery drain either. Only a 3 ft. difference in elevation gain/loss over 4,000 ft. Total elevation gain/loss in Topofusion is only 4 ft. different.

Elapsed Time:	3:53:05
Moving Time:	3:52:11
Topofusion moving time: 3:52:36

http://connect.garmin.com:80/activity/embed/122756861


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