Correcting bad GPS data on Strava

Arlberg
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Correcting bad GPS data on Strava

Postby Arlberg » Fri May 04, 2018 4:38 pm

Hello all,

I'm just wondering if anyone knows of how to repair dodgy GPS data files from Strava rides? I have a handful of rides where the loss of my Garmin Edge GPS signal (usually caused by going through a tunnel or a narrow gorge etc) meant that the Garmin lost the signal temporarily, and took me off the actual route I rode and I therefore I lost a few Strava segments. The annoying thing is it often seems to happen on a never to be repeated ride/route or when pushing up an ascent for a good time! There used to be a website called Raceshape that allowed Strava users to correct route data but it seems to have been discontinued.

Is there any easy way to do it? I have about half a dozen rides I would like to correct from rides in Europe.

g-man
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Re: Correcting bad GPS data on Strava

Postby g-man » Fri May 04, 2018 7:19 pm

Have you tried fitfiletools.com ?

I’ve used it before with some success.

Arlberg
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Re: Correcting bad GPS data on Strava

Postby Arlberg » Sun May 13, 2018 2:02 pm

Thanks for that G-man, do you mean the 'Section Remover' part? I tried it but after I removed the corrupt section (which was only one waypoint) the file was no longer recognised by Strava when I went to upload the ride again. It would probably work if simply removing the start or end of a ride rather than a middle bit. With Raceshape one was able to drag the wayward waypoint(s) back onto the route thereby not corrupting the file.

Anyone got any other suggestions?

And if someone out there with know-how is really bored and has nothing better to do, I could send them the corrupted rides and you could have a go at fixing them..... :roll:

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bychosis
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Re: Correcting bad GPS data on Strava

Postby bychosis » Sun May 13, 2018 2:50 pm

I’ve auvcessfully removed sections from rides. It does require editing the gpx file though. I used notepad in windows. The hard part is finding the data that is wrong. Once found, delete that point/section making sure you remove all the data for the offending points. I can’t remeber what the markers are for the start and end of a point, but I worked it out by checking the start of the file to see which bits were repeating at what interval.
bychosis (bahy-koh-sis): A mental disorder of delusions indicating impaired contact with a reality of no bicycles.

Arlberg
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Re: Correcting bad GPS data on Strava

Postby Arlberg » Sun May 13, 2018 3:44 pm

Thanks bychosis. I'm not that savvy and what you describe is beyond me. To remove the corrupted section I just looked at the map and deleted the part of the ride between where the moving dot went off the road and came back onto it again. It is usually just one or two wayward waypoint(s) (or around a hundred metres or so of riding) and looks like a triangle with the wayward waypoint at the apex.

You can see one example here (of about 5 or 6 that I have) on the ascent of the Stelvio.

https://www.strava.com/activities/683303473

I got a 'KOM' for my ascent only because I was the fastest up the climb on the route calculated by Strava with the dodgy waypoints. Funnily enough it seems that since I did it three other riders also must have lost their GPS signal in the same place as me as there are now four of us on the segment comparison. You can see there are two spikes caused by a signal loss (there are tunnels there), one from the ascent and one from the descent.

As with all the rides I have where this problem has occurred, I'm trying to remove the dodgy waypoints so I can be on the official Strava segment for the ascent and compare myself legitimately with all other riders.

Arlberg
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Re: Correcting bad GPS data on Strava

Postby Arlberg » Thu May 17, 2018 6:06 pm

Anyone on here bored (and talented) enough to wanna have a go at downloading the ride file and removing the dodgy way point(s) (caused by going through a tunnel on the ascent) by clicking on the link to the ride in the above post and which meant that my Garmin didn't record the official segment for the Stelvio ascent?

I would be really very grateful!! :D

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A_P
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Re: Correcting bad GPS data on Strava

Postby A_P » Thu May 17, 2018 7:37 pm

try garmin base camp
work on a copy of the original gpx file if you still have it , otherwise the downloaded gpx will no have timestamp information = wont re-upload
you can drag and drop individual waypoints and save etc
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find_bruce
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Re: Correcting bad GPS data on Strava

Postby find_bruce » Thu May 17, 2018 8:36 pm

Arlberg wrote:my Garmin didn't record the official segment for the Stelvio ascent?
Which do you think is the official segment see for example Vincenzo Nibali

As for editing, try Viking GPS editor - easy enough to use, just move the points to where you want them, you can manually adjust the times. Just be aware that if time runs backwards at any point Straa will reject the upload.

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kb
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Re: Correcting bad GPS data on Strava

Postby kb » Fri May 18, 2018 1:10 pm

I’m tempted to have a crack with the original FIT file if you have it. You can email it to kbilleter@gmail.com. Might take a couple of days to find the time though...

K
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Arlberg
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Re: Correcting bad GPS data on Strava

Postby Arlberg » Sun May 27, 2018 8:15 pm

Thanks kb, that would be wonderful if you could, I’ve sent you an email.

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kb
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Re: Correcting bad GPS data on Strava

Postby kb » Sun May 27, 2018 9:22 pm

Arlberg wrote:Thanks kb, that would be wonderful if you could, I’ve sent you an email.

Hi,

Try to get to it shortly but woke up in hospital Friday night / Saturday morning. Apparently hit or was hit by a car on the way home - don’t even remember th day properly anymore. Nothing seems terrible buts all a little achy currently so will be pretty quiet for a week or two (if that’s possible with a 16 month old). Next currently in a brace due to a fractured c7. There a couple of broken ribs too :-(
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find_bruce
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Re: Correcting bad GPS data on Strava

Postby find_bruce » Mon May 28, 2018 2:47 pm

kb wrote:Hi,

Try to get to it shortly but woke up in hospital Friday night / Saturday morning. Apparently hit or was hit by a car on the way home - don’t even remember th day properly anymore. Nothing seems terrible buts all a little achy currently so will be pretty quiet for a week or two (if that’s possible with a 16 month old). Next currently in a brace due to a fractured c7. There a couple of broken ribs too :-(

Ouch kb, heal well

Arlberg
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Re: Correcting bad GPS data on Strava

Postby Arlberg » Tue May 29, 2018 7:25 pm

Oh I’m very sorry to hear that kb, I wish you a speedy recovery.

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