A Lexis surface is a Cartesian mapping of three attributes to three dimensions:
- year (or another measure of absolute time) to the x axis,
- age (or another measure of relative time) to the y axis,
- a third variable, which co-varies with year and age, to the z axis.
Put another way: a Lexis surface is a way of visualising temporal change as if it were spatial change, of thinking about time as if it were space: of absolute time as if it were latitude, relative time as if it were longitude, and a third variable as if it were a height above sea level. Continue reading “Lexis cubes 1: From maps of space to maps of time”