Although I missed the live race for the second time in a row, and didn’t get a chance to play with the data as quickly as I would have liked to, I did spend some of my time away wondering how to plot all the telemetry data for a driver captured during a race in a single graphic.
The single lap view, like this one from one of Button’s laps at the 2010 Malaysian Grand Prix:
is all very well, but if we overlay traces from each lap onto the distance labeled x-axis, the charts just become messy to read.
So how about this instead. On the x-axis, we have the distance traveled round the track per lap. The drivers are pretty consistent in the lines they take, so the overall distance is pretty consistent. If we have a 4km track, and a chart that’s 400 pixels wide, each pixel corresponds to 10m resolution of track distance. For the y-axis, we use the lap number. And to plot the actual value of a telemetry measurement, let’s use colour. Put these together, and we come up with some driver DNA charts – the ones below are form Hamilton:
So how do you read these? Each strip is a different measure. The colour intensity increases with increasing value up to the maximum recorded value. Within each strip, time flows down the strip.
The top, blue strip shows the gear (1 to 7); the green strip shows the throttle pedal depression (0-100%), and the red strip shows the brake (0-100%). The light blue strip is a composite of the previous three strips. The whiter the pixel, the closer it is to 100% throttle in 7th gear with no braking.
The bottom two traces show the longitudinal and lateral g-force respectively. For the longitudinal trace, red shows braking – being forced into the steering wheel; green shows acceleration – being forced back into your seat. You’ll see the greatest g-force under braking occurs when the brakes are slapped full on… (the red bits in the third and fifth traces line up). For the latitudinal g-force, the red shows the driving being flung to the left (i.e. right hand corner), the green shows them being pushed out to the right.
I’m slowly pulling enough tools together to be able to start telling some stories… so stay tuned ;-)