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Visualizaiton workshop at UBC B.I.G. Research Day. 11 May 2016


visualization + design

Christopher Hitchens—Out of Letters

ASCII Art

The images shown here were created as part of my ASCII Art project, which extends ASCII art to include

  • proportionally spaced fonts
  • a variety of font weights in a single image
  • both tone and structure of the image to select characters
  • fixed strings to render an image in legible text

Applying the code to images of Hitchens was motivated by my own deep love of Hitchens and a typographic portrait of Christopher Hitchens, created out of Gill Sans letters by Miles Chic at Capilano University.

This adds to my growing shrines to Hitchens, including Merry Hitchmas! and hitchslap t-shirts.

Christopher Hitchens in Letters and Words

All images are generated using Gotham, with up to 8 weights (Extra Light to Ultra). Each image includes size and characters used for the image. I give the absolute type size, though only useful to know in relative terms to the size of the image and other images drawn with the same method. The color of text in each layer is the same—black— but font weight may vary.

Some images are generated using more than one layer of ASCII. In some cases the characters used in each layer are different.

basic ascii

As the font size is reduced, greater detail and contrast can be achieved.

Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 43pt set: . x 8 : * @ - \ | _space_ / (source from Christian Witkin/Twelve/Grand Central Publishing) (zoom, source)
Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 29pt set: . x 8 : * @ - \ | _space_ / (source from Christian Witkin/Twelve/Grand Central Publishing) (zoom, source)
Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 17pt set: . x 8 : * @ - \ | _space_ / (source from Christian Witkin/Twelve/Grand Central Publishing) (zoom, source)
Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 11pt set: . x 8 : * @ - \ | _space_ / (source from Christian Witkin/Twelve/Grand Central Publishing) (zoom, source)

By setting the image with a fixed string, such as a short quote or longer body of text, detail is lost but the ASCII representation takes on more meaning.

Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 11pt set: godisnotgreat (source from Christian Witkin/Twelve/Grand Central Publishing) (zoom, source)
Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 29pt set: godisnotgreat (source from Christian Witkin/Twelve/Grand Central Publishing) (zoom, source)
Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 11pt set: Hitchslap 11 (source from Christian Witkin/Twelve/Grand Central Publishing) (zoom, source)
Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 5 layers (11pt -6deg, 17pt 6deg, 29pt -3deg, 43pt 3deg, 59pt 0deg) set: godisnotgreat (source from Christian Witkin/Twelve/Grand Central Publishing) (zoom, source)
Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 7pt set: . x 8 : * @ - \ | _space_ / (source from Gasper Tringale) (zoom, source)

multi-layered ascii art

Images take on detail when multiple rotated layers of text is used. Each of the images below is composed of more than one layer, starting with a 2-layer image which uses the uppercase alphabet at 0 and 90 degrees.

Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 2 layers (0deg, 90deg) set: A-Z (source from HBO) (zoom, source)

Meaning can be added to the image by using different text in each layer. In the examples below, I set the same image using the pair "Godisnotgreat" (at 0 degrees) and "religionpoisonseverything" (at 90 degrees). In the second example, I use the unlikely combination of "Jesus" and "Mohammad"—inspired by Jesus and Mo.

Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 2 layers set: Godisnotgreat. 0deg Relionpoisonseverything. 90deg (source from HBO) (zoom, source)
Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 2 layers set: Jesus 0deg Mohammad 90deg (source from HBO) (zoom, source)

When rotated layers contain punctuation, very high level of detail can be achieved.

Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 2 layers set: . : - + * _space_ 0deg / 90deg (zoom, source)

The image below is made out of layers that contain only forward (/) and back (\) slashes.

Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 2 layers set: \ / (zoom, source)

The image below is made using only the period character in three layers rotated at -45, 0 and 45 degrees. Although the image looks like a pixelated version of the original—it is more than that. It is a typeset representation that uses 8 weights of Gotham. Character spacing between periods is informed by font metrics.

Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 2 layers set: . (zoom, source)
Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 2 layers set: 8 X x | ^ : . - = + ' " @ \ / | * ~ , # (source from The Australian) (zoom, source)

hitchens at the podium

The three images below show the difference between using a variety of punctuation characters and setting an image using a block of text. The first image uses "8 X x" and common punctuation.

Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 11pt set: 8 X x | ^ : . - = + ' " @ \ / | * ~ , # (zoom, source)

I use hitchslap 9 for the first image below, and all the hitchslaps for the second image. When setting an image in using a block of text, the choice of character at any position is fixed and only the font weight is allowed to vary. When the text is relatively short (e.g. hitchslap 9 is 544 characters and is repeated 50 times in the image), rivers of space appear in the image.

Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 11pt set: Hitchslap 9 (zoom, source)
Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 11pt set: all Hitchslaps (zoom, source)

In both cases, the image is very recognizable.

recursive ascii art

When an image of text is set with the text itself, you have recursive ASCII art. Below is hitchslap 2, set with itself. In the image, the font is Gotham and the text used to asciify the image is also Gotham.

It makes ordinary moral people, compels them, forces them, in some cases orders them do disgusting wicked unforgivable things. There's no expiation for the generations of misery and suffering that religion has inflicted in this way and continues to inflict. And I still haven't heard enough apology for it. — Christopher Hitchens

The quote is 307 characters long and is repeated 391 times in the image.

Christopher Hitchens - ASCII Art / Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Christopher Hitchens ASCII Art. method: Gotham font, 8 weights, 11pt set: Hitchslap 2 (source from hitchslap 2) (zoom, source)

In principle, the process of asciifying text with text can be repeated, by using the asciified image as input for asciification with progressively smaller text.

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news + thoughts

Regression diagnostics

Wed 11-05-2016

Residual plots can be used to validate assumptions about the regression model.

Continuing with our series on regression, we look at how you can identify issues in your regression model.

The difference between the observed value and the model's predicted value is the residual, `r = y_i - \hat{y}_i`, a very useful quantity to identify the effects of outliers and trends in the data that might suggest your model is inadequate.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Nature Methods Points of Significance column: Regression diagnostics? (read)

We also discuss normal probability plots (or Q-Q plots) and show how these can be used to check that the residuals are normally distributed, which is one of the assumptions of regression (constant variance being another).

Background reading

Altman, N. & Krzywinski, M. (2016) Points of Significance: Analyzing outliers: Influential or nuisance? Nature Methods 13:281-282.

Altman, N. & Krzywinski, M. (2015) Points of Significance: Multiple Linear Regression Nature Methods 12:1103-1104.

Altman, N. & Krzywinski, M. (2015) Points of significance: Simple Linear Regression Nature Methods 12:999-1000.

...more about the Points of Significance column

Analyzing Outliers: Influential or Nuisance?

Fri 08-04-2016

Some outliers influence the regression fit more than others.

This month our column addresses the effect that outliers have on linear regression.

You may be surprised, but not all outliers have the same influence on the fit (e.g. regression slope) or inference (e.g. confidence or prediction intervals). Outliers with large leverage—points that are far from the sample average—can have a very large effect. On the other hand, if the outlier is close to the sample average, it may not influence the regression slope at all.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Nature Methods Points of Significance column: Analyzing Outliers: Influential or Nuisance? (read)

Quantities such as Cook's distance and the so-called hat matrix, which defines leverage, are useful in assessing the effect of outliers.

Background reading

Altman, N. & Krzywinski, M. (2015) Points of Significance: Multiple Linear Regression Nature Methods 12:1103-1104.

Altman, N. & Krzywinski, M. (2015) Points of significance: Simple Linear Regression Nature Methods 12:999-1000.

...more about the Points of Significance column

Typographical posters of bird songs

Mon 28-03-2016

Chirp, chirp, chirp but much better looking.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
The song of the Northern Flicker, Black-capped Chickadee, Olive-sided Flycatcher and Red-eyed Vireo. Sweet to the eye and ear. (details)

If you like these, check out my other typographical art posters.

Happy 2016 Pi Day—gravity of `\pi`

Mon 14-03-2016

Celebrate `\\pi` Day (March 14th) with colliding digits in space. This year, I celebrate the detection of gravitational waves at the LIGO lab and simulate the effect of gravity on masses created from the digits of `\\pi`.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
1,000 digits of `\pi` under the influence of gravity. (details)

Some strange things can happen.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
44 digits of `\pi` under the influence of gravity. (details)

The art is featured in the Gravity of Pi article on the Scientific American SA Visual blog.

Check out art from previous years: 2013 `\\pi` Day and 2014 `\\pi` Day and 2015 `\\pi` Day.