Theory of Data Graphics Part 1 Most of a graphic’s ink should vary in response to data variation (see chapters 4-6)
Chapter 4 - Data-Ink Ratio Data Ink is the ink on a graph that represents data. Tufte claims that good graphical representations maximize data-ink and erase as much non-data-ink as possible. Data-Ink Principles: 1. Above all else show data. 2. Maximize the data-ink ratio. 3. Erase non-data-ink. 4. Erase redundant data-ink. 5. Revise and edit
Data-Ink ratio of 1 Tufte tests these principles on a whole range of examples to come up with a wide range of fresh designs that dramatically improve the legibility of the graphs. Here is an example with a very high data-ink ratio. It’s an electroencephalogram – a graph that records the electrical activity from the brain. This graph would have a data-ink ratio of 1.
CH. 5 - Chartjunk Moiré vibration 1 2 3123 Grids 1 vs 212 Ducks (self-promoting graphs that are used to demonstrate the graphic ability of the designer rather than display the data.)
Worst chart ever? “A series of weird three-dimensional displays appearing in the magazine of American Education in the 1970’s delighted the connoisseurs of the graphically preposterous. Here five colors report, almost by happenstance, only 5 pieces of data (since the division within each adds to 100%). This may well be the worst graphic ever to find its way into print.” See page 118.
Multifunctioning Graphical Elements “The same ink should often serve more than one graphical purpose” (139) Graphical element may carry data information and also perform a design function Element that locates or plots the data is the data measure, also pg. 144 “road stripes”
Multifunctioning Graphical Elements Data-Based Grids Grid reports directly on the data Sometimes it’s better to make the coordinate labels into the actual data points themselves. (this strategy eliminates the need to perform eye-work) example exampl Generally works better for smaller data sets
Multifunctioning Graphical Elements Puzzles and Hierarchy in Graphics Complexity of the elements can sometimes turn the graphic into a visual puzzle How to recognize: Graphic must be interpreted through verbal rather than visual process See page 153