柱状图把值编码为同一基线上矩形的长度。威廉·普莱费尔，1786年《商业与政治图集》。
工作报告、广告与作业中适合一次性比较少量类别。若类别过多、3D 或双轴，换一种形式。
Rules
- 规则 1 — Use 同一基线上矩形的长度 as one channel, not two.
- 规则 2 — Direct labels beat a distant legend.
- 规则 3 — Do not hide zero. If you break the axis, say so.
- 规则 4 — Colour encodes category or magnitude, not both.
- 规则 5 — Put the claim in the title, not just “柱状图”.
- 规则 6 — Source and period, even in small type.
Palette
- 色板 1 — Categories: distinct hues. Sequences: one hue, changing value.
- 色板 2 — Diverging: a neutral centre, emphasis at both ends.
- 色板 3 — One brand colour plus greys beats a rainbow.
- 色板 4 — Check contrast on a projector and in greyscale print.
Type
- 文字 1 — Tabular figures for numbers. Do not pour body copy into the chart.
- 文字 2 — Titles as sentences; axes as short nouns.
- 文字 3 — For CJK, drop weight one step and leave tracking.
柱状图: honour 同一基线上矩形的长度, and switch when 类别过多、3D 或双轴.