Timeline encodes values as position along an ordered time axis. Joseph Priestley’s 1765 Chart of Biography inspired later atlases.
In reports, ads and assignments it fits ordered events, eras, project milestones. Skip it when you need quantities changing, not just dates.
Parts
- Mark — The core mark of Timeline is position along an ordered time axis.
- Scale — The scale must show zero (or a declared break) and units.
- Axis — Axis titles name the variable, not a mood.
- Legend — A legend is weaker than a direct label. Write beside the mark when you can.
- Label — Numbers are optional. If comparison is the job, label the ends only.
- Grid — Keep the grid faint. Data should own the ink.
- Annotation — One annotation sentence. Date the source.
- Frame — A thin frame. Never a 3-D box.
Variants
- Chronology — Variant 1 of Timeline. Same encoding, different layout.
- Gantt cousin — Variant 2 of Timeline. Same encoding, different layout.
- History rail — Variant 3 of Timeline. Same encoding, different layout.
- Timeline 4 — Variant 4 of Timeline. Same encoding, different layout.
Labels
- Axis — On Timeline, make Mark readable.
- Legend — On Timeline, make Scale readable.
- Label — On Timeline, make Axis readable.
- Grid — On Timeline, make Legend readable.
- Annotation — On Timeline, make Label readable.
Timeline: honour position along an ordered time axis, and switch when you need quantities changing, not just dates.