# The Visual Display of Quantitative Information

by Edward Tufte

★★★☆☆

Finished

## Graphical excellence

complex ideas communicated with clarity, precision and efficiency.

that which gives to the viewer the greatest number of ideas in the shortest time with the least ink in the shortest space

graphical excellence is nearly always multivariate

And graphical excellence requires telling the truth about the data

## Data-Built data measures

Using the data itself to plot data "increases the quantitative detail and dimensionality of a graphic"

If we are going to make a mark it may as well be a meaningful one. The simplest—and most useful—meaningful mark is a digit. (Tukey)

### Examples:

• stem-and-leaf
• "Living histograms"
• Complex data measure encodings, e.g. plot of Chernoff faces

## Color guidance

Color often generates graphical puzzles. Despite our experiences... the mind's eye does not readily give a visual ordering to colors.

Greyscale shades show varying quantities better than color.

## Multiple layers of information

1. What is seen from a distance, an overall structure usually aggregated from an underlying microstructure.
2. What is seen up close and in detail, the fine structure of the data
3. What is seen implicitly underlying the graphic

Consider the viewing architecture of a graphic.

## Data-ink ratio

Data-ink is the non-erasable core of a graphic, the non-redundant ink arranged in response to variation in the numbers represented.

$\texttt{data-ink ratio} = \frac{\texttt{data-ink}}{\texttt{total ink used to print the graphic}}$

### Whitespace

Even part of the data measures can be erased, making a white grid

### range-frame

the frame of a graphic can become an effective data-communicating element simply by erasing part of it.

should extend only to the measured limits of the data

## Data density

Taking into account the size of the graphic in relation to the amount of data displayed yields the data density:

$\texttt{data density of a graphic} = \frac{\texttt{number of entries in data matrix}}{\texttt{area of data graphic}}$