Visualising multi-sport events

Today, I participated in my first duathlon — 5 kilometres of running, followed by 32 kilometres of cycling, and finishing with another 5 kilometres of running:

As I do with my separate running or cycling sessions, I record my performance (HR, power output, pace) and upload it to Strava and intervals.icu. It surprises me, however, that there is no clear way of combining these separate activities into one multi-sport event. I assume there’s much to gain when looking at these activities in their context, rather than separately.

As a small side project, I could look into the best way of combining the different .fit-files into one well-visualised multi-sport event. It would surprise me if no one else has done this before, but this idea gives me the best opportunity to dive into how these files are structured (as I am totally unfamiliar with how they work) and how I could combine them in one multi-sport visualisation.

I could use the data from different .fit-files to display some maps of the course and compare the first and last running segments of a duathlon, for example. I could show a well-visualised race timeline with interesting annotations like weather conditions and elevation profiles, and the location of the highest achieved heart rate and power output. For friend groups participating in the same event, I could show different participants’ data on the same visualisation, to easily let them compare their performance.