Monday, May 8, 2017

A New Chart Type - Race Concordance Charts

Although this blog doesn't attract that many comments, one of the repeated ones has been for a wider scope in battlemaps so that they show more than just the lead chasing or chased car.

To a certain extent, the track position charts provide a macroscopic overview of the race as a whole from a track position viewpoint, and race history charts show the relative pace of different vehicles.

But how about a chart that could provide a view of the track, both ahead and behind, within a certain time window, from the perspective of a particular car?

This is where track concordance charts come in. For each lap, these charts show the cars ahead - and the cars behind - a particular target car, giving you an at a glance view, on a lap by lap basis, of the traffic ahead and behind the target car, on track.

Here are a few examples of original sketches from the 2017 Russian F1 Grand Prix:


The circles represent cars ahead (negative acctimedelta, in seconds, to the left) and behind (positive acctimedelta, in seconds, to the right) the target vehicle. The colour identifies the lap the cars are on - pale blue is the same racing lap, dark blue shows cars a lap ahead (that need to be let by under blue flag conditions), and orange (to red) are backmarkers behind. The highlights within a circle marker are used to denote other target cars. The vertical, y-axis identifies the lap the target car is on.

In the top chart, the ivory coloured vertial bars represent the pit window, a time +/- pit loss time away from the target car. Vertical dashed lines identify the lap or laps on which the target car pitted.

One of the things our eyes detect in the charts are the progressions of a particular car, assuming they lie along a perceived line. (Aren't the principles of the Gestalt Theory of Perception wonderful?!)

We can actually make traces of a particular car explicit by using a line to connect them. Note that we also need to break the line where the trace for a particular car skips a lap, so we don't get a "carriage return" line across the canvas:


We can also play with the window size:
To my eye these charts are harder to read than the simpler scatterplot style race concordance charts. In certain respects, they are reminiscent of race history charts, providing an idea (from the gradient) of particular lines) of the pace of other cars nearby on track over several laps, relative to the pace of the target car. Additional annotations, such as pit lines and pit windows, may add useful value to this chart without further complicating the reading of it (indeed, they may make it easier to read).

For more detail about the origins of the race concordance chart, see: Race Track Concordance Charts.


7 comments:

  1. I agree with you about the first set of charts being easier to read. I also like the idea of blue flag blue for those that are a lap ahead.

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  2. It's cool that the concordance charts represent the traffic so well. I do think I slightly prefer the battle maps since they are easier to read. This is mostly because of your naming scheme in the battle map allows me to understand what's happening without (much) prior knowledge of the race. Maybe for the line graph version of the concordance you could map the team color to the trace instead of using the default color palette?

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    1. Hi Jake

      Thanks for the feedback... re: colours - agreed; I could maybe also use thickness or shade to distinguish the drivers; I also need to add a key or some sort of line label. Another thought was to very faintly ghost the lines on bottom layer of the scatter plot. Will look at this more this w/e if I get a chance.

      In the dot plot, I should also add a legend for highlighted drivers...

      Never ceases to amaze me how in the dot style plots our eyes manage to pull "continuous" lines out... Gestalt theory of perception ftw:-)

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    2. Yeah I had colors on the brain because I just worked out the color-constructor mapping for a F1 plotting app. Thickness of line or dashed/dotted/solid is a good idea distinguish the two drivers!

      Bring on Barcelona!

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  3. @jake Re: F1 plotting app - nice; I had a shiny dashboard thing for ergast data that I need to revisit and add to Wrangling Data book at some point. (Btw, the /more info/ link to http://jacobwarner.net/ is borked on the app page (it's relative to AWS URL).)

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    1. is ergast the API you use for the data? I'm looking for something like that. The app above scrapes statsf1.com.

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    2. Some of the above charts are powered by ergast data, yes... ( I need to update the Info link at the bottom to include that.)

      The code I use is here: https://github.com/psychemedia/wranglingf1datawithr/blob/master/f1djR/R/ergastR-core.R There may still be issues with it but I fix them if I come across them. It really needs some cacheing added so it doesn't keep hitting the API repeatedly for the same data if I do make repeated calls to it.

      I also have scrapers that scrape the same - and more - data from FIA pdfs. I use this for the quali laptimes, for example.

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