Space-Time Graphics: Narratives of Space and Time

Overview

Space-time graphics place a spatial dimension (route position, stations, distance along a path) on one axis and time on the other, so a moving entity traces a line whose angle encodes its speed, whose crossings reveal encounters, and whose density reveals congestion. The form was developed by the Paris engineer Charles Ybry in his 1846 British patent for railway scheduling, and it extends to any phenomenon that moves or develops through both space and time at once. (The famous Paris–Lyon chart is VDQI material — EI never connects Ybry to it, and VDQI p. 31 notes Marey himself credited that schedule to the engineer "Ibry.") The payoff: one flat graphic narrates what Tufte calls a "four or five variable story" — places, times, identities, speed — without a table of numbers (EI p. 101).

Source note (read this first). The substance here lives in Envisioning Information (EI), the chapter "Narratives of Space and Time," pp. 97–119 — Galilean satellites pp. 97–101, itineraries and timetables pp. 101–113, dance notation pp. 114–119 — with the grid-weight progression stated in EI p. 59 and The Visual Display of Quantitative Information (VDQI) pp. 115–116. Visual Explanations (VE) itself redirects this material: its footnote 12 (p. 93) points the reader to EI pp. 32, 45, 97–113. VE's key related display is the Salyut-6 cyclogram (pp. 92–95), a time-by-time grid — see §13, which bridges this skill to VE.

§1. The Canonical Axis Setup

The standard graphical timetable for a linear route:

Station placement: stations sit as horizontal bands or tick lines at their true proportional distance from the terminus. Unequal real spacing produces unequal vertical gaps — that is correct. Forcing equal vertical spacing onto unequal distances corrupts every slope on the chart.