Data to ink ratio

Towards production

Roland Krause

MADS6

Friday, 6 December 2024

Introduction

Material

Fundamentals of data visualisation

Chapter 17

The Visual Display of Quantitative Information, Edward Tufte

What is good data visualisation?

Your turn

Form groups of two or three people
Collect the data visualisation principles you consider important
Prepare these statements in writing

Examples for discussion

Delirium

Protein complexes

Numbers inside pie charts represent the percentages of total proteins (a) and complexes (b–f). Outer labels show partitioning of the data according to the chart function.

Gavin et al, Nature, 2002

Data visualization principles

Reducing data-ink ratio

Five Laws of Data-Ink

Above all else: Show the data!
Maximize the data-ink ratio.
Erase non-data ink.
Erase redundant data-ink.
Revise and edit.

Edward Tufte

Data-ink ratio

Definition of data-ink

The non-erasable core of a graphic. Everything but the plot background.

Formal definition

Data-ink divided by the total ink used to print the graphic.
The proportion of a graphic’s ink devoted to the non-redundant display of data information.
One minus the proportion of a graphic that can be erased without loss of data information.

Displaying the length of genes

gene	length
SCN1A	1002
ACT1	921
SLC1A3	801
IRG1	789
SCN4A	600
SCN5A	585
SCN2A	543
APO42	120

Standard plotting with Excel

OK, remove 3D

Basic pie chart

OK, let’s make it a bar chart

Bar chart

Remove coloring of bars by length, recolor by standard palette

Bar plot with categorical colors

Sort the bars!

Sorted

Rotate

The largest on top

Remove the legend - redundant

Self-explanatory bar chart

Simplify title and description

New plot title, no surplus legend

Use the available space

Increase data to ink

Remove grey background!

White background

Absolute numbers in bars, remove x-axis

Free bars

Remove color

Minimal display

But you know …

gene	length
SCN1A	1002
ACT1	921
SLC1A3	801
IRG1	789
SCN4A	600
SCN5A	585
SCN2A	543
APO42	120