Data-Ink

class: middle, center, title-slide

# Data-Ink
## STAE04: Data Visualization
### Johan Larsson
### The Department of Statistics, Lund University

---

## Data-Ink

Consider how you are spending the **ink** in a visualization.

data-ink <a name=cite-tufte2001></a>([Tufte, 2001](#bib-tufte2001)): the ink used to draw data

$$
`\begin{aligned}
\text{data-ink ratio} 
&= \frac{\text{data-ink}}{\text{total ink used in visualization}}\\ 
&= 1 - \text{proportion of a graphic that can be erased}
\end{aligned}`
$$

### Tufte's Principles

.pull-left[
* Above all else show the data.
* Maximize the data-ink ratio.
* Erase non-data ink.
* Erase redundant data-ink.
* Revise and edit.
]

.pull-right[
<img src="images/tufte.png" width="80%" style="display: block; margin: auto;" />

]

---

## Above All Else Show the Data

<div class="figure" style="text-align: center">
<img src="images/playfair-england-usa.jpg" alt="William Playfair, The Commercial and Political Atlas (1786). Public domain." width="80%" />
<p class="caption">William Playfair, The Commercial and Political Atlas (1786). Public domain.</p>
</div>

---

## Above All Else Show the Data

<div class="figure" style="text-align: center">
<img src="images/playfair-nordic-england.jpg" alt="William Playfair, The Commercial and Political Atlas (1786). Public domain." width="80%" />
<p class="caption">William Playfair, The Commercial and Political Atlas (1786). Public domain.</p>
</div>

---

## Maximize the Data-Ink Ratio

Non-data-ink may distract your audience from what really matters: the data.

Maximizing the data-ink (within reason) is a good rule-of-thumb.

.pull-left[
<div class="figure" style="text-align: center">
<img src="06-data-ink_files/figure-html/unnamed-chunk-4-1.png" alt="low data-ink ratio" width="360" />
<p class="caption">low data-ink ratio</p>
</div>
]

.pull-right[
<div class="figure" style="text-align: center">
<img src="06-data-ink_files/figure-html/unnamed-chunk-5-1.png" alt="high data-ink ratio" width="360" />
<p class="caption">high data-ink ratio</p>
</div>
]

---

## Redundant Data-Ink

**redundant** data-ink: ink displaying information already shown by other ink

.pull-left[
<div class="figure" style="text-align: center">
<img src="06-data-ink_files/figure-html/unnamed-chunk-6-1.png" alt="lots of redundant ink" width="360" />
<p class="caption">lots of redundant ink</p>
</div>
]

.pull-right[
<div class="figure" style="text-align: center">
<img src="06-data-ink_files/figure-html/unnamed-chunk-7-1.png" alt="no redundancy" width="360" />
<p class="caption">no redundancy</p>
</div>
]

**note:** redundancy is not always bad

---

## ggthemes

**ggthemes** <a name=cite-arnold2019></a>([Arnold, 2019](https://CRAN.R-project.org/package=ggthemes)) provides a theme and some custom
plots for ggplot2

.pull-left[

```r
library(ggthemes)
ggplot(mpg, aes(drv, cty)) +
* geom_tufteboxplot() +
* theme_tufte(base_size = 16)
```

<img src="06-data-ink_files/figure-html/unnamed-chunk-8-1.png" width="360" style="display: block; margin: auto;" />
]

.pull-right[

```r
ggplot(mpg, aes(drv, cty)) +
  geom_boxplot(
    stat = "fivenumber"
  )
```

<img src="06-data-ink_files/figure-html/unnamed-chunk-9-1.png" width="360" style="display: block; margin: auto;" />
]

---

## References

<a name=bib-arnold2019></a>[Arnold, J. B.](#cite-arnold2019) (2019).
_ggthemes: Extra Themes, Scales and Geoms for 'ggplot2'_. R package
version 4.2.0. URL:
[https://CRAN.R-project.org/package=ggthemes](https://CRAN.R-project.org/package=ggthemes).

<a name=bib-tufte2001></a>[Tufte, E. R.](#cite-tufte2001) (2001). _The
Visual Display of Quantitative Information_. Second. Cheshire, CT, USA:
Graphics Press. ISBN: 978-1-930824-13-3.