One of the issues with the original session utilisation chart (example) is that it doesn't represent lap time in an observable way (the times are only represented by segment size), so in this variant, I try a colour mapping to highlight the faster laptimes, and suppress the pit stops....
Is this any more meaningful? One thing I think it's lacking is a radial divider to separate out the sessions? (Not sure hwo to do that yet!)
Here's a side by side comparison with the previous style:
The Protovis color mapping I'm using is dependent on laptime. The values I used were guessed at, so I need to come up with a principled way of setting them. It may also be worth experimenting with a log scale:
.fillStyle(pv.Scale.linear(85,95,110).range('red', 'green', 'lightblue'))
I don't know if "lightblue" is a valid colour, (maybe it's breaking something....!) but I got the effect I wanted!
I added the thin blue boundary to provide a means to pull together the data from the two drivers into a meaningful whole. This also acts as a prompt to me to look in more detail at the Gestalt Theory of Visual Perception...