Bicycling mag vs Strava



Subliminal-SS

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Sep 4, 2013
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Hi Bob,


I've attached an image so you can see my experiences. Obviously here we are playing with different devices so to draw likeness is guesswork at best. But this is the solution I found to my Strava Random elevation woes. Thing is I know the Garmin810 was writing the file in Raw data and using its own interpretation of it for elevation calculation. Indeed Training peaks would actually read lower than garmin so my guess is Garmin probably Chopped out the micro ups and downs. TrainingPeaks was using some form of algorithm based on continual increase. Again just chopping out the up one down two up thee feet type data whereas strava just added the whole lot together and produced an elevation profile from that.

The only thing I can think is that in the Files its now reading from there is an elevation gained constant written at the end of the activity. When I had to chop my Wattage data out of a TCX/GPX(I forget) it had a max and average watts value in there so I'm thinking something similar. Trouble is the FIT file is gibberish so I can read that.

I did however copy and paste my Fit file off the device and upload that directly to Strava via upload from file. It hit me with the same value as the device did. It must be writing to a constant somewhere in the file.

Whatever you have as your elevation on your device in the ride history will be the correct one. I would go from there as the correct value. I know training Peaks allows you to edit the Elevation Gained value and thats what I have been doing for proper tracking and then ignoring strava until now.

What does the dive write to in default. Is it a .fit file in your rides folder on the device's memory?

 
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CAMPYBOB

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Sep 12, 2005
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Jon,

Thank you for your assistance!

The Cateye Stealth does not have a readout screen for altitude gain so I can not compare the website values to the device. Mileage, speed, average speed and time all appear to match the device with max. speed sometimes reported higher on STRAVA by tenths of a MPH to maybe 4 MPH for some reason. No big deal and probably just a triangulation error or loss of signal error during a descent.

Max. heart rate and cadence on the websites appear to match my device screen observations as I ride. Accurate values there.

All file uploads to the various website appear to accurately match the heartrate, speed, distance and cadence sensor readings on the device and they match each other closely. Only the altitude values are FUBAR.

I just re-read the Cateye Stealth 50 Owner's Manual and I can not find what format the native file format is stored as.

It 'may' be a .CES format, as this is the format used by the Cateye Sync software to upload the ride data from the device to Cateye's Atlas website (a factory supported log site similar to STRAVA/Training Peaks/Map My Ride/Bike Route Toaster etc.).

Thru the Cateye Snyc software, I directly export to the Atlas website, to STRAVA and to Training Peaks. I have to export/save a file to my computer to get it to Map My Ride and I had been using .GPX format to do that.

File export options from the Sync software are: .CES (proprietary?), .GPX, .FIT, .ETD, .CSV (last two used for E-Train and I would suppose comma separated for spreadsheets). I think there is another file format available for export, but I don't have access to my device and dock right now to see what it is.

Again, thanks for sharing your experience with your Garmin 810...a device I just may be buying next! Christmas is coming and I'm pretty sure Garmin has more time working with GPS coords than Cateye.

Lastly,

"...and then ignoring strava until now."

Same here. Right now I'm tossing the STRAVA elevation data as it is the one so far out in left field. And...it 'may' be the most accurate. The other sites do fall more in alignment with each other whether right or wrong. It's too bad as STRAVA is probably the most popular site and most used for web-based social cycling.

So far, I enjoy using STRAVA and MMR over the others for their features and for the speed they run at on my DSL connection.

I agree with your theory that the website altitude algorithms are where the interpretations are skewing the graphed values. But...and it's a very deep, dark 'but'...can an algorithm be so different in its 'smoothing', 'chopping' or whatever to yield and error of THREE to one or more?
 

CAMPYBOB

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"Downhill KOMs, especially on segments that go right through stop signs? Thanks but no thanks."

I unknowingly and incidentally did a 6-mile STRAVA segment...with 4 stop signs on it. So, to move from 3rd place to 1st place all I have to do it blow 4 stops signs.

Hey, only 2 of them cross state routes...

I think I'll stay happy with a 3rd rather than commit Stravacide! Cyber trophies don't mean squat and the obummercare websites are still crashed...
 

Subliminal-SS

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Sep 4, 2013
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Thats to bad that you couldnt get it sorted. However just as I was uplaoding my ride to strava I did notice in the upload section under the From Garmin Tab it does say "Dont have a garmin device, upload direct from the device".

As soon as I started exporting and not using the original device files thats when everything went off for me. It sucks that you cant upload the actual device file.

I would agree with you that there is no way an algorithm should be able to be so far out but I can see why also. Strava's elevation calculator was built (now I know this one in particular) with the smoothing to already be applied to the various files. The funniest one was when I was on my Turbo trainer and I did 2000ft of climbing all because my room fan was blowing in circles in front of the device so the elevation was bopping up and down like a yoyo. Everything else cut this out as "noise" but Strava added all the little ups and downs and declared me as having climbed 2000ft...
 

CAMPYBOB

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Heh! You won the "King of the Fan" climb!

I do upload direct (kinda/sort of...thru the Cateye Sync software/firmware dock) to Atlas, STRAVA and Training Peaks. It's only MMR that I have to actually export & save a file to then upload the website. But, yeah...if that .CES format is native and proprietary it sucks to be a Cateye user!

I am going to try using some of the "Upload From Device" website options. I have notice very limited support for devices other than Garmin. Being the big dog has its advantages. I'm guessing my future experience will be similar to yours and I have just got to figure out which combination of uploads, files and and sites yield some level of correlation.
 

CAMPYBOB

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I'm using the free STRAVA and the other device option only allows me to upload from my computer. STRAVA does support Timex Run Trainer 2.0 though. Upload Your Activities
Searching for Devices...
No Garmin devices found Search again or Upload a file directly from your computer. For more details and tips on troubleshooting your device, see our Knowledge Base.

Your browser is not supported by the Garmin Communicator Plugin. The Garmin plugin currently supports: Internet Explorer 6+, Firefox 1.5+ on Win, 2.0+ on Mac, and Safari 2.0+ You may also upload a file directly from your computer
Your device is not supported by Strava For more details and tips on troubleshooting your device, see our Knowledge Base.
No activities were found on your device
Using a Garmin device? Install the Garmin Communicator plugin.
It helps Strava communicate directly with your device and upload the files.
Using another type of device? Upload files directly from your computer.
 

Subliminal-SS

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Sep 4, 2013
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Quote: Originally Posted by Subliminal-SS .
However just as I was uploading my ride to strava I did notice in the upload section under the From Garmin Tab it does say "Dont have a garmin device, upload direct from the device".


Sorry I meant to exclude that Line. That was from memory and after I double checked I saw that the line re-directs you to put in a file.

It does suck that Strava doesn't really seem to give a rats **** about much. I get the impression they'd like everyone to use their app tbh.

I checked out the cateye website though and their response was IMHO worse.. It basically said if there are elevation differences then sites interpret the data differently, only use the figure as a rough guide. Really poor stance on that one really considering Elevation Gain is a big stat for people without power meters etc having climbed twice the height you did 6 months ago and still feeling good is a great achievement and one you want to see in the numbers.
 

CAMPYBOB

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Yes, we pay from $100 to $500 for...a 'rough' approximation.

I was achieving the same figures just using a manual intersection-to-intersection manual route creation. I bought the GPS computer to save route creation time AND increase accuracy and confidence in the numbers.

Sadly, the Cateye Stealth/websites fail on both counts.

Despite Cateye having released Sync software upgrades, it is still glitchy. It may take me one attempt to directly upload files and it may take me ten or more attempts to upload. The Sync software keeps giving me "Device Not Found" errors (WTH? It's right there in the USB-connected dock!) and then when the file finally starts uploading, it interrupts the upload with a "Communication Error".

****.

So much for saving time and convenience...

To buy an 810 for Christmas or wait for higher resolution, more accurate GPS in the next generation? Maybe an App for the phone?
 

Subliminal-SS

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Sep 4, 2013
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Well that certainly all sounds like a flaky system.

I was on the resolution/Iphone app park but it was just outright taking to long.

I like the display on the 810 it didnt look amazing but it really is a good looking display. I particularly enjoy being able to create an interval workout and then have the Device tell me I need to do 10 mins at X wattage speed etc. Personally this is the best feature for me doing a fair bit of indoor training and its not even advertised.

I also wouldn't mind getting an 800 its a great device and you can get some cracking deals on those.

Unfortunately the 810 isnt without its own issues. the TBT is useless but it does backup to the routes drawn on the map so I normally just follow that. Other than its Navigation issues its been really good for me and the latest firmware does a good job except the guiding me.
 

bartsie

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Jun 20, 2011
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The concept of total elevation gain is based upon the understanding that if you look at the route profile closely enough at each point, it turns into a straight line. Then if this line heads up then you add to the total elevation. Then add all the straight pieces up.

Back when I was an undergraduate ages ago I got my hands on Benoît Mandelbrot's book on fractals (it's still in print). He describes curves that do not become straight no matter how much you magnify them and therefore don't lend themselves easily to e.g. evaluating the length. He gave an example of a border between Spain and Portugal, and the length of this common border, according to Spanish vs Portuguese authorities, differ by a third (well it's been 30 years so I don't remember exactly, but it was striking). Serious stuff, national border, not some local climb.
 

CAMPYBOB

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Sep 12, 2005
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"Unfortunately the 810 isnt without its own issues. the TBT is useless but it does backup to the routes drawn on the map so I normally just follow that. Other than its Navigation issues its been really good for me and the latest firmware does a good job except the guiding me."

Thanks for the info. I like the mapping on the 810. That has to be cool when riding new areas.

The Stealth actually works well on the road. The recording of data has been solid and the display is both readable and logical in layout. The uploading of data is not rock solid by any means. Frankly, Microsoft could have done a better job. The Sync software works about as well as Windows ME. And Cateye's Atlas website is pretty slow on my DSL (but, at least it does load). The Atlas GPS point editing function sucks (MMR seems to do best for that function).



"Serious stuff, national border, not some local climb."

Rui Costa approves of your post!

It's not so much that I'm looking for the absolute length of the Spanish-Portuguese border down to the thousandth of a millimeter. It's more like I'm trying to get the Cateye Spanish to stop telling me the border is actually with France.and the STRAVA Portuguese to stop calculating it's location is along the Rhine River and Training Peaks to stop telling me all borders are fascist.

If we can put a Cruise missile thru a fourth story window of a building 1300 nautical miles from launch, accounting for coriolis effect...you'ld think a few nerds could get a conference call going to use the exact same data to yield somewhat 'close' GPS data.

And no...you don't even want to know the results of yesterday's workout with the kiddies. We did a flatter interval/sprint course and Cateye Atlas shows MORE climbing than the hillier and longer route the day before. All righty then!

I've also been noticing the caloric 'guesstimations' have erratic and illogical ratings. Not that I care <grabs beer>.

You know those 'fake' display clear stick-on overlays with a fake display of sample screen numbers that bike computers come with to protect the plastic screen and give the prospective buyer a picture of what it looks like? I might as well have left mine on...