Temporal Data Area
This section discusses design options for the main display of the data points.
Regularity/Irregularity of Time Flow
Almost all visualisations show a regular progression of time, despite the fact that the data distributions are often strongly ‘bunched’ or stretched out. Often vertical bands within the main data area are used to lay out the information in a ‘waterfall’ pattern (top left flows to bottom right) to make the best use of space when bunching occurs. Empty regions often are left simply empty.
In these representations colour is commonly used to indicate categories of event.
The main data area typically consists of horizontally stratified information groups. Lifelines from the medical record domain is a good example.
Annotations cross the horizontal bands when necessary. In the following picture vertical lines indicate descendants.
Reverse Time Flow
An emergency response visualisation by the influential Stamen design team also uses colour to good effect.
Newer calls to 911 shown in red, and fade to blue as they age. This is one of the few applications where time flows right to left.
Temporal Colour Encoding
This timeline of papers and citations uses time bar colour within the main data area to good effect.
One can clearly see the later citations (red). Size is used for the number of citations.