In this chapter Edward Tufte examined three major topics: the motion of Jupiter’s satellites, itinerary and timetable design, and the notation systems for dance movements

In the first part, Tufte talked about the evolving representation of Jupiter’s satellites. When Galileo started to get interested in the satellites of Jupiter, he represented their movement with simple diagrams on his notebook. In the diagram, Jupiter and its satellites were drawn as dots of different shapes. They are aligned in different sequences according to their relative position Galileo observed from the sky. Later, Galileo constructed Jovilabes with the others, and the representations of the satellites’ movements evolved from dots to continuous curves that report every positions. The representation was updated again, in the end, the Voyager spacecraft revealed the true image of satellites.

In the second section, Tufte described a series of timetables and route maps, each with its own advantages and shortcomings. He started with looking at examples of comprehensive description of a transport system requires both time and spatial experience. The map for the Czechoslovakia Air Transport Company, and the China Railway Timetable Index Page were used as good examples here of how complex network of routes and times can be shown at the same time in limited space. After discussions on timetable and train schedules, he mentioned some strategies can be used in data representation: serpentined data formations, which is especially useful when data are lognormally distributed; spilled outlying data; and end-to-end cylinder/circular graphic. I think the three strategies can be really useful on different datasets, even though they may also cause confusion and misunderstanding.

Lastly, Tufte talked about notations of dance movement, which is defined as the process of “translate human body movement into signals transcribed on flatland”. I totally agreed with Tufte that the notations themselves can be something elegant and beautiful that are independent from the motions they represent. The diagrams from Dictionary of Kinetography are almost like drawings themselves.