Thanks very much for this. I tried it with a couple files from a wired SRM and Garmin 500. It seems to work well except the tcx output file doesn't seem to contain the speed or cadence data. Any chance you can include speed and cadence?

I sure can give it a try. Send me your files via PM. I'll see what i can do.

Am glad to hear that some PC7 afficionados and wired SRM users here are already making good use of SRM2STRAVA.

I just updated the code and it now includes the cadence field. As far as the speed is concerned, i left it out as Strava derives the speed from the GPS coordinates via their own algorithm.


Let me know if you need more info

Thanks for the quick update!

 
You are welcome.

While synchronizing the SRM and GPS files is not exactly trivial it is not that complicated either. In part, the attraction of SRM2STRAVA comes from how well it ends up working and its user-friendliness. It's only natural that i would follow-up on your suggestion.

Just to give everyone a quick overview of how it works, take a look at the graphs below. This was from a ride where i turned on the Strava Phone app well before i started rolling out of the parking lot. Also, note we took a nice long coffee break in the middle. We also stopped near the end and regrouped. A typical ride.


The bottom graph shows the SRM and GPS speed vs time. Considering that the time on the PowerControl may or may not be set properly, that we typically turn each device on at different moments, we cannot expect the two graphs to match. That said, we can see that this is just a matter of shifting one of the graphs by a few hundred seconds. SRM2STRAVA does that automatically and more often than not, it gets it right on the first pass. You can see on the top graph that after applying the correct lag, 241 seconds in this case, the two graphs match really well and we have a satisfactory synchronization.

Once this lag is known, it becomes rather easy to populate the wattage, heart rate and cadence fields of the tcx files with the values recorded by the PowerControl.

Sometimes, though, the R2 value for the correlation can be pretty low. That does not necessarily mean that the synchronization is bad. Visual inspection can quickly tell whether the synchronization is good or not. Low R2 values are often due to intermittent GPS or speed sensor signal loss, numerous start/stop, low sampling rate for either device and such.

If both the R2 value and the visual inspection point to a bad synchronization, one can try moving the sliders in the left panel to shift the start times and see if the synchronization improves. The graphs will be updated on-the-fly. While i am sure it will happen, I have yet to find a case where a satisfactory synchronization could not be found.

Hope this helps.

Thank you to all of you who provided feedback here or by PM.

Some problematic cases have been brought to light in the process. We have made some corrections and the back-end code should handle these cases better.

If you experienced some issues with SRM2STRAVA, I encourage you to try it again and/or to contact me directly.

Best regards,

Just a quick note to let you know that .pwx files (Peaksware exchange file format) are now supported.

Supporting the .pwx file format means that we can now process Powertap power data whether it is coupled to a LYC or a Joule, not just SRM and PowerControl data.

As a bonus, supporting .pwx files also means that it doesn't quite matter what software is used to download the data from your cyclocomputer/powermeter combo of choice. SRMWin, GoldenCheetah, DeviceAgent/WKO+, PowerAgent, SRM, Powertap, Quarq, LYC, PowerControl, Joule, Garmin, wired, wireless... it works. You can now enjoy Strava's power analysis features.

To try it, go to http://www.coursealavant.com and choose the PWX2STRAVA tab

Don't hesitate to contact me if you need more info.

This is fantastic! Exactly what I was looking for, since I've got an old Powertap that doesn't have GPS capabilities. I tried it out using a downloaded Strava .gpx file from my phone, and then a .pwx file that came from my Powertap (via Golden Cheetah), and it looks like the power numbers are a little funky / almost not there. http://www.strava.com/...s/185315218/overview

Any thoughts? Thank you!

Sorry to hear you're having problems with it.

Use the contact info at http://www.coursealavant.com to get in touch. I'd like to take a look at the files.