Page 1 of 2 1 2 LastLast
Results 1 to 25 of 34
  1. #1
    Join Date
    Nov 2005
    Location
    Making the Bowl Great Again
    Posts
    13,780

    Tracking the amount you climb.

    Fuck off stravasshole, etc. Yeah, got it.

    That said, I am curious about elevation gain in rides. I have searched and there are numerous threads about why Trailforks thinks you climb more than Strava, even when they are sharing data. But none of them attempt to answer which is more accurate.

    Maybe it doesn't matter at all, but I think it's nice to know what I actually climb on rides I know so I know what to expect when I go places I haven't been. A lot of this is because I am fat, slow, and stupid, but still.

    Back to my point:

    • I did a new-to-me ride last week that Strava said had 2092 feet of gain but Trailforks claims 2685.
    • A local loop is 2550 according to Strava, but over 3005 according to Trailforks.
    • Another local loop is 3420 according to Strava but 4073 according to Trailforks.



    Does anyone have any more info on this? I suppose the logical follow-up is that if Trailforks is at least consistent, then a local ride that climbs 3500 should have more or less the same amount of climbing than some ride I'm looking at that it also says has 3500, right?

  2. #2
    Join Date
    Oct 2007
    Posts
    12,664
    Always go with the higher number. Duh.

  3. #3
    Join Date
    Feb 2012
    Location
    Missoula
    Posts
    2,104
    What are you using to record? A cell phone's GPS is less accurate than a garmin or something, especially when it comes to determining elevation, and especially when you're in the mountains and forest where it can't see as many satellites, especially ones that are not right above you.

    A dedicated gps usually uses a barometric pressure sensor to help determine your elevation, because with a couple of satellites above you it is pretty hard to determine your exact elevation. This is fine, except that the actual barometric pressure often changes which would result in the gps device thinking you are changing elevation.

    Strava/garmin/trailforks etc can also try to correct your elevation based on topo data, but that is only as accurate as the map data and your gps track, so there is also a lot of potential for variation there.

    So the answer is that your ride elevation data is never going to be "exact." I don't worry much about it and it usually seems close enough. Still, it's a little annoying when I'm on a mountain or whatever where I know the elevation and my garmin is reading hundreds of feet different. Like last weekend I was up on point 6, elevation 7940, and my garmin says I was only at 7624. Still the overall gain for the ride seemed to be in the right ballpark.

  4. #4
    Join Date
    May 2012
    Location
    People's Republic of OB
    Posts
    4,437
    My rides usually include a few trails linked together so Trailforks isn't as useful for that. I usually import or draw in tracks into other software and link them into a route if I need to get stats. I find they can all be off depending what base map is being used to pull elevations from. Accuracy of tracks loaded into TF will vary too especially if it comes from a smartphone app, and on steep terrain this can exaggerate errors. I only use my Garmin for recording rides. It overstates distance but elevation is usually about right. Never bothered comparing it to TF and I don't use strava.

  5. #5
    Join Date
    Aug 2008
    Location
    Central VT
    Posts
    4,808
    I have riding buddies who have Garmin GPSs that link to their Strava. I’m told those are most accurate for vert and mileage.

    Strava is all over the place when I’m on a group ride and we compare numbers afterwards.


    Sent from my iPhone using TGR Forums

  6. #6
    Join Date
    Feb 2012
    Location
    Missoula
    Posts
    2,104
    What are you using to record? A cell phone's GPS is less accurate than a garmin or something, especially when it comes to determining elevation, and especially when you're in the mountains and forest where it can't see as many satellites, especially ones that are not right above you.

    A dedicated gps usually uses a barometric pressure sensor to help determine your elevation, because with a couple of satellites above you it is pretty hard to calculate that accurately. This is fine, except that the actual barometric pressure changes due to temperature and weather which results in the gps device thinking you are changing elevation even if you stay in the same place.

    Strava/garmin/trailforks etc can also try to correct your elevation based on topo data, but that is only as accurate as the map data and your gps track, so there is also a lot of potential for variation there.

    So the answer is that your ride elevation data is never going to be "exact." I don't worry much about it and it usually seems close enough. Still, it's a little annoying when I'm on a mountain or whatever where I know the elevation and my garmin is reading hundreds of feet different. Like last weekend I was up on point 6, elevation 7940, and my garmin says I was only at 7624. Still the overall gain for the ride seemed to be in the right ballpark.
    Last edited by jamal; 08-01-2018 at 03:19 PM.

  7. #7
    Join Date
    Nov 2005
    Location
    Making the Bowl Great Again
    Posts
    13,780
    Yes, a phone. But I have had three different phones over the last three summers and the same rides are essentially identical on each phone as tracked by Strava. My understanding is that neither Strava nor Trailforks use GPS elevation data, "and instead generate elevation for each lat/lng point in your ride." https://www.trailforks.com/help/view/90/

  8. #8
    Join Date
    May 2012
    Location
    People's Republic of OB
    Posts
    4,437
    Quote Originally Posted by HankScorpio View Post
    Strava is all over the place when I’m on a group ride and we compare numbers afterwards.
    Obviously half the group are cheating bastards then. Strava!!

  9. #9
    Join Date
    Jan 2008
    Location
    BC to CO
    Posts
    4,888
    If you really want to know, here is a good blog on the discrepancies with recording devices and the data averaging that they do:
    http://regex.info/blog/2015-05-09/2568

  10. #10
    Join Date
    Dec 2007
    Location
    Hell Track
    Posts
    13,931
    Strava doesn't register a change in elevation unless it's (I believe) 30 feet or more. Trailforks registers elevation changes of (I believe) .5 feet. So if you drop the same GPS file into each program, they'll show different amounts of climbing.

    The more consistently uphill the trail is, the closer the outputs will be. But particularly on flatter sections and rolling trails, trailforks registers way more vert just because a lot of those rolls aren't big enough to register on strava. With such small amounts of elevation change registering, trailforks would theoretically register a jump as a small climb (although I'm sure the accuracy of that varies based on your gps device).

    I find both to be reasonably accurate compared to themselves (i.e. if I do the same ride a few times, the numbers are generally consistent). So for myself, I just track my vert with strava because it's more convenient. But if I was going to brag about it on tgr, I'd obviously use trailforks.

    Sent from my SM-G950U using Tapatalk

  11. #11
    Join Date
    Aug 2014
    Location
    Imaginationland
    Posts
    4,797
    Trailforks is not even close to accurate. I've checked it against my altimeter and topo maps. They always overshoot.

  12. #12
    Join Date
    Oct 2003
    Location
    Aspen
    Posts
    9,436
    Quote Originally Posted by HankScorpio View Post
    I have riding buddies who have Garmin GPSs that link to their Strava. I’m told those are most accurate for vert and mileage.

    Strava is all over the place when I’m on a group ride and we compare numbers afterwards.


    Sent from my iPhone using TGR Forums
    Is everyone uploading with their phones or some on GPS and some with phones?

    I've found my Garmin to be way less accurate and more variable than Strava on my iPhone. I've found my iPhone to be pretty damn accurate based on known elevations.

  13. #13
    Join Date
    Nov 2005
    Location
    Making the Bowl Great Again
    Posts
    13,780
    Quote Originally Posted by NW_SKIER View Post
    Trailforks is not even close to accurate. I've checked it against my altimeter and topo maps. They always overshoot.
    I don't have a response to your altimeter comparison but I am not sure a 40' topo map provides the level of detail necessary to compare. Of course, this also raises the quesiton about how Trailforks uses topo maps to calculate elevation gain/loss in the small increments toast is noting.

  14. #14
    Join Date
    Sep 2006
    Location
    Seattle
    Posts
    880
    Strava auto corrects elevation to topo data unless your device has a barametric altimeter (most Garmins do). Some people turn off this correction (you can in settings) because it typically reduces your "elevation gained" on a ride. So if your friend went into the strava settings and turned this off, they'll show inflated elevation numbers

    I wouldn't trust anything from trailforks.

  15. #15
    Join Date
    Dec 2010
    Posts
    3,936
    Quote Originally Posted by toast2266 View Post
    Trailforks registers elevation changes of (I believe) .5 feet. So if you drop the same GPS file into each program, they'll show different amounts of climbing.

    The more consistently uphill the trail is, the closer the outputs will be. But particularly on flatter sections and rolling trails, trailforks registers way more vert just because a lot of those rolls aren't big enough to register on strava. With such small amounts of elevation change registering, trailforks would theoretically register a jump as a small climb
    Quote Originally Posted by NW_SKIER View Post
    Trailforks is not even close to accurate. I've checked it against my altimeter and topo maps. They always overshoot.
    This makes sense. One particular downhill trail has about 30 seconds of climbing midway in and the rest is downhill. Trailforks says the trail is 300' of climbing, while strava registers 30' of climbing. Sounds like trailforks is measuring every little pop, and rise, root and rock haha. I guess that adds up.

    I bet according to trailforks Crabapple hits is close to a climbing trail haha.

  16. #16
    Join Date
    Oct 2003
    Location
    slc
    Posts
    17,980
    Quote Originally Posted by ridinshockgun View Post
    I wouldn't trust anything from trailforks.
    I tried using the Trailforks ride tracking feature once and it dropped the track a bunch of times. It was a route I'm unlikely to repeat so I was pretty bummed. Never again.

    Toast's explanation makes a lot of sense. The TF file for the BMT trail at Snowbird, for instance, says there's over 800' of climbing. There's zero feet of actual climbing.

  17. #17
    Join Date
    Feb 2008
    Location
    Donner Summit
    Posts
    1,251
    Quote Originally Posted by jamal View Post
    What are you using to record? A cell phone's GPS is less accurate than a garmin or something, especially when it comes to determining elevation, and especially when you're in the mountains and forest where it can't see as many satellites, especially ones that are not right above you.
    iPhone 6 and later use barometric pressure for elevation.

  18. #18
    Join Date
    Jan 2008
    Location
    BC to CO
    Posts
    4,888
    Quote Originally Posted by funkendrenchman View Post
    Is everyone uploading with their phones or some on GPS and some with phones?

    I've found my Garmin to be way less accurate and more variable than Strava on my iPhone. I've found my iPhone to be pretty damn accurate based on known elevations.
    I find the opposite.
    I record exclusively with my Garmin.
    Mrs Hubbs records exclusively with her iPhone.
    When I compare the data from trails or loops we repetitively do together our results always vary from each other.
    My garmin data recorded is very consistent to the data of the same trail on previous rides, where as her iPhone produces varied data every time on the same trail.
    Some days her mileage is 15% more than me, some days 15% less. And elevation is really all over the map when she records by iPhone.

  19. #19
    Join Date
    Dec 2009
    Posts
    1,703
    My Garmin also has settings to how often it records data (older Garmin 500), if I remember correctly, the settings are every 2sec vs every 5 or 10sec (for best battery savings)

  20. #20
    Join Date
    Oct 2003
    Location
    slc
    Posts
    17,980
    I tracked a ride over the weekend with Strava that I had last recorded 3 years ago with MyTracks on a much older phone and the total recorded vert was within about 100 ft. Virtually no difference in mileage, either.

  21. #21
    Join Date
    Jan 2006
    Location
    Carbondale
    Posts
    12,497
    Those of you checking vs. topo, are you adding in the down and reclimb of the same vert vs the start elevation and top elevation?

    I just use strava on the iPhone, and it's OK... and I know that and don't need something gnats ass.
    www.dpsskis.com
    www.point6.com
    formerly an ambassador for a few others, but the ski industry is... interesting.
    Fukt: a very small amount of snow.

  22. #22
    Join Date
    Oct 2005
    Location
    Wasatch
    Posts
    6,256
    Yesterday, I beasted out my stiffest climb of this season. I use a TomTom watch to record. It dumps to the TomTom app. The TomTom app is linked to Strava. I usually pay attention to Strava and ignore the initial output from the watch. It was 3,800 feet vs. 2,700 feet when I checked today!

    3,800 sure makes me feel better about the fact that I felt like I was going to puke, but now I am just perplexed. Some of the ride was on rolling terrain on Mid Mountain and Keystone, but could that have been a 1k difference?

  23. #23
    Join Date
    Sep 2006
    Location
    Seattle
    Posts
    880
    Quote Originally Posted by Sirshredalot View Post
    Yesterday, I beasted out my stiffest climb of this season. I use a TomTom watch to record. It dumps to the TomTom app. The TomTom app is linked to Strava. I usually pay attention to Strava and ignore the initial output from the watch. It was 3,800 feet vs. 2,700 feet when I checked today!

    3,800 sure makes me feel better about the fact that I felt like I was going to puke, but now I am just perplexed. Some of the ride was on rolling terrain on Mid Mountain and Keystone, but could that have been a 1k difference?
    You can likely turn on elevation correction with your TomTom app. I know you can with Garmin even if it does have an altimeter. If using strava, it's probably best to just use elevation correction across the board. If everyone did this, it would all be the same for the same ride...for the most part.

  24. #24
    Join Date
    Aug 2008
    Location
    Central VT
    Posts
    4,808
    Quote Originally Posted by funkendrenchman View Post
    Is everyone uploading with their phones or some on GPS and some with phones?

    I've found my Garmin to be way less accurate and more variable than Strava on my iPhone. I've found my iPhone to be pretty damn accurate based on known elevations.
    I use my iPhone like a pleb, a couple other guys I ride with use separate fancy GPSs. I hope for their sake they're more accurate considering they paid hundreds for them. I'm not very tech savvy so Stravadouching it is fine with me.

  25. #25
    Join Date
    Dec 2005
    Location
    in the dark
    Posts
    2,199
    "A man with a watch knows what time it is. A man with two watches is never sure." (link)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •