Improved Analysis of Power Curves

First a quick note as I write this, since the new ConnectStats service was introduced, the new service has now passed the 1 million activities threshold out of 14,000 users who used the new service rolled out in January! It is small compared to the big players, but nice nonetheless.

After working on improving the calculation of the best rolling curves, I have now implemented a first version of an improved summary analysis.

In the new version 6.0 of ConnectStats you can now explore your power curves or best rolling plot and study when you reached you best and compare in detail how you are improving over time.

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Daily exercise in lockdown

We are living through strange times. I live in London and we are currently in lockdown/stay at home order for a few weeks now. I am quite lucky that my family and myself didn’t get infected by the virus and are still healthy. We are following the rules and staying home except for the daily exercise. Luckily in London, unlike in France where some of my family lives, we are allowed to bike and run without a constraints to stay too close to home (one kilometre in france), as long as we leave and come back from our home it’s ok.

As the weather has been gorgeous since the beginning of the lockdown, this enabled me to log quite a few nice runs and ride.

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Units and Translations

ConnectStats tries to maintain for each field in an activities from Garmin or Strava a list of translations and units for the metric or imperial system. I am mostly my-self using the app in English and metric but I had updated the list in different languages from some sources I had found online and the Garmin website a few years ago.

But it is now a bit dated and there are quite a few attributes for which I do not have the translations. Some users volunteered to update the translations in their native language. In addition recently I received quite a few bugs report about units being incorrect for example for elevation or weights.

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Debugging with Xcode and Python time series calculations

Trying to understand what was wrong in my Best Rolling Curve Calculation pushed my ability to use Xcode debugger to its limit. The quirks I was trying to understand were happening on large time series after multiple level of sampling, rolling averages, etc on noisy data.

I ended up in a mixed environment so I could easily exchange time series data between Xcode and pandas in a Jupyter notebook, which enabled me to explore and get to the bottom it!

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Chasing Complex Bugs: Power Curves and Best Rolling Curves

The harder category of bugs are when it is related to bad numbers generated from the more complex algorithms in ConnectStats. This is what is now happening with the best rolling plots.

The rolling best curve are one of my favorite feature in ConnectStats, they provide insight I don’t see in many other services. It’s quite common to see a power curve, but I feel the concept extended to heart rate or speed help give people a good sense of the characteristic of a workout. While the concept is simple, it actually can be a bit tricky to implement (at least for me it was). The current version of the app shows quite a few quirks that are obviously wrong, like the below.

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Chasing bugs never ends

I am now stuck at home as many of us. Weather out is beautiful. So I’ll take the opportunity of the extra time to try to write more about the app development. One source of inspiration that never seem to end is chasing bugs in the app! So while I have the time at home, I’ll try to detail them as I chase them! Starting with some database woes…

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New version fixing old legacy code

ConnectStats has been around for a while now. It started in 2011, while the Garmin API was in a very different place as today. I have maintained it over the years, but there is still quite a bit of complexity in the code due to the history of the API evolution.

I am pushing a new version that simplifies some of the legacy internals of the code.

As any internal upgrade, it will help in the future and fixes some side effect or bugs coming from the legacy complexity. But it also comes with high risk as it is hard to test all the side effect. I’ll try to fix what comes out.

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Quick review of COVID-19 data

While I am still preparing a new release of ConnectStats fixing a few issues, right now, the corona virus is a major distraction for most of us. While the virus spreads there is a lot of information floating around and it can be sometimes be a bit confusing. So I decided to see what could I verify on my own at home with basics analysis and tools. I’ll be using python/jupyter/pandas, which is very standard and easy to install or can be run directly on google collab

This may become a bit technical for some, but hopefully will be interesting and may help some people learn more about python and pandas as more of us have to stay home…

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Never ending service and server saga

Time flies. It has been close to one year since Garmin opened its new API to third party developers and that I embarked on migrating ConnectStats to using it. I had anticipated it would be fairly straight forward, but, boy, it has been quite a ride, and the last few weeks continued to provide a lot of “excitement”. Let me share some of that story…

Quick recap of the service

In the past ConnectStats was connecting to the Garmin Connect website to extract the data for the user activities. While this was the way ConnectStats worked from the beginning (2011!!!), it was simple as I didn’t have to maintain any online servers, but it was not very robust and repeatedly created serious outage as the Garmin Connect website would change its way of getting data without any type of support or documentation. I would typically have to find out via a multitude of bug report and try to reverse engineer what had changed on the web site.

The new service is fully documented and supported, but the flip side is that it works by pushing the fit files of a user to the application web server in the cloud. Which means you need to have a web server in the cloud, which I didn’t…

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Data Privacy in ConnectStats

I recently saw a negative review on the App Store for ConnectStats warning users that ConnectStats is not a Garmin app and therefore people should avoid giving away login information in the app as the data may get stolen.

Keeping data secure both on your phone or online has been a key guiding principle in how I tried to implement the app. So while I understand the concern, I felt it was a bit unfair.

I have been careful to make sure the data isn’t shared and the passwords are never sent to me. I also made the app open source so that people can check for themselves what it is doing.

I felt it may be worth to write a bit of details on what is ConnectStats doing with your data and password, with link to the code. So people can either let me know if I miss something or feel better about using the app.

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