resources
visualizations
presentations
lunch break
Distractions and amusements, with a sandwich and coffee.
visualization + design
buy artwork
`\pi` Day 2015 Art Posters
On March 14th celebrate `\pi` Day. Hug `\pi`—find a way to do it.
For those who favour `\tau=2\pi` will have to postpone celebrations until July 26th. That's what you get for thinking that `\pi` is wrong. I sympathize with this position and have `\tau` day art too!
If you're not into details, you may opt to party on July 22nd, which is `\pi` approximation day (`\pi` ≈ 22/7). It's 20% more accurate that the official `\pi` day!
Finally, if you believe that `\pi = 3`, you should read why `\pi` is not equal to 3.
Not a circle in sight in the 2015 `\pi` day art. Try to figure out how up to 612,330 digits are encoded before reading about the method. `\pi`'s transcendental friends `\phi` and `e` are there too—golden and natural. Get it?
This year's `\pi` day is particularly special. The digits of time specify a precise time if the date is encoded in North American day-month-year convention: 3-14-15 9:26:53.
The art has been featured in Ana Swanson's Wonkblog article at the Washington Post—10 Stunning Images Show The Beauty Hidden in `\pi`.
This year's art has a modern Bauhaus style. Sharp edges, lines and solid colors. Potato farms from space. CPUs from up close. If the pieces look like the art of Piet Mondrian, you'd be right.
buy artwork
The digits of `pi` are encoded in something that looks like a treemap. I explain how this is done in the methods section, but before reading it, try to see if you can figure out how it's done.
buy artwork
I briefly experimented with the 4-color theorem in trying to apply color to the treemap, but it turned out to lack interesting stucture. Well, at least some graphs were made.
I experimented with different treemap resolutions. For treemaps that use an outline around each rectangle, I decided to stop at 8 levels, at which 111,469 digits of `pi` can be encoded.
buy artwork
buy artwork
buy artwork
I also made a level 9 treemap without the outlines, which encoded 612,330 digits. When rendered at 20,833 × 20,833 pixels (I needed the image in bitmap form to provide the posters for sale), some regions are essentially a pixel in size, as seen in the 1-1 crop below.
Treemap art and history
If you enjoy treemaps, explore Ben Shneiderman's History of Treemaps and Treemap Art.
VIEW ALL
news + thoughts
Music for the Moon: Flunk's 'Down Here / Moon Above'
The Sanctuary Project is a Lunar vault of science and art. It includes two fully sequenced human genomes, sequenced and assembled by us at Canada's Michael Smith Genome Sciences Centre.
The first disc includes a song composed by Flunk for the (eventual) trip to the Moon.
But how do you send sound to space? I describe the inspiration, process and art behind the work.
Happy 2021 `\pi` Day—
A forest of digits
Celebrate `\pi` Day (March 14th) and finally see the digits through the forest.
This year is full of botanical whimsy. A Lindenmayer system forest – deterministic but always changing. Feel free to stop and pick the flowers from the ground.
And things can get crazy in the forest.
Check out art from previous years: 2013 `\pi` Day and 2014 `\pi` Day, 2015 `\pi` Day, 2016 `\pi` Day, 2017 `\pi` Day, 2018 `\pi` Day and 2019 `\pi` Day.
Testing for rare conditions
All that glitters is not gold. —W. Shakespeare
The sensitivity and specificity of a test do not necessarily correspond to its error rate. This becomes critically important when testing for a rare condition — a test with 99% sensitivity and specificity has an even chance of being wrong when the condition prevalence is 1%.
We discuss the positive predictive value (PPV) and how practices such as screen can increase it.
Altman, N. & Krzywinski, M. (2021) Points of significance: Testing for rare conditions. Nature Methods 18:224–225.
Standardization fallacy
We demand rigidly defined areas of doubt and uncertainty! —D. Adams
A popular notion about experiments is that it's good to keep variability in subjects low to limit the influence of confounding factors. This is called standardization.
Unfortunately, although standardization increases power, it can induce unrealistically low variability and lead to results that do not generalize to the population of interest. And, in fact, may be irreproducible.
Not paying attention to these details and thinking (or hoping) that standardization is always good is the "standardization fallacy". In this column, we look at how standardization can be balanced with heterogenization to avoid this thorny issue.
Voelkl, B., Würbel, H., Krzywinski, M. & Altman, N. (2021) Points of significance: Standardization fallacy. Nature Methods 18:5–6.
Graphical Abstract Design Guidelines
Clear, concise, legible and compelling.
Making a scientific graphical abstract? Refer to my practical design guidelines and redesign examples to improve organization, design and clarity of your graphical abstracts.
"This data might give you a migrane"
An in-depth look at my process of reacting to a bad figure — how I design a poster and tell data stories.
