R ggplot2绘制条形图时如何调整Y轴覆盖不同数量级数据

跨3个数量级的数值用线性Y轴必然会导致低量级数据被压缩，常规断轴、手动调断点效果差的核心原因是线性刻度无法适配大跨度数量级差异，直接用ggplot2内置的对数刻度即可实现参考图效果，不需要依赖第三方包，也不需要给轴加断裂标记。

修改后完整可运行代码 #

library(ggplot2)

ggplot(data, aes(x = reorder(Treatment, -mean), y = mean))+
  geom_bar(stat="identity", fill="black" , alpha=0.5)+
  geom_errorbar(aes(ymin=mean-se, ymax=mean+se), width=0.4, colour="black", alpha=0.9, size=1.3)+
  # 核心Y轴配置，覆盖1e-9~1e-7三个量级
  scale_y_log10(
    breaks = c(1e-9, 1e-8, 1e-7),
    labels = c(expression(10^-9), expression(10^-8), expression(10^-7)),
    limits = c(8e-10, 1.2e-7)
  )+
  theme(
    line = element_line(colour = "black", size = 1, linetype = 1, lineend = "butt"), 
    rect = element_rect(fill = "white", colour = "black", size = 1, linetype = 1), 
    aspect.ratio = 1,
    plot.background = element_rect(fill = "white"),
    plot.margin = margin(1, 1, 1, 1, "cm"),
    axis.text = element_text(size = rel(2.5), colour = "#000000", margin = 1), 
    strip.text = element_text(size = rel(0.8)), 
    axis.line = element_blank(), 
    axis.text.x = element_text(vjust = 0.2), 
    axis.text.y = element_text(hjust = 1), 
    axis.ticks = element_line(colour = "#000000", size = 1.2), 
    axis.title.x = element_text(size = 30, vjust=0.5), 
    axis.title.y = element_text(size = 30, angle = 90), 
    axis.ticks.length = unit(0.15, "cm"), 
    legend.background = element_rect(colour = NA), 
    legend.spacing = unit(0.15, "cm"), 
    legend.key = element_rect(fill = "grey95", colour = "white"), 
    legend.key.size = unit(1.2, "lines"), 
    legend.key.height = NULL, 
    legend.key.width = NULL, 
    legend.text = element_text(size = rel(2.0)), 
    legend.text.align = NULL, 
    legend.title = element_text(size = rel(2.0), face = "bold", hjust = 0), 
    legend.title.align = NULL, 
    legend.position = c(.80, .88), 
    legend.direction = NULL, 
    legend.justification = "center", 
    legend.box = NULL, 
    panel.background = element_rect(fill = "#ffffff", colour = "#000000",
                                    size = 2, linetype = "solid"), 
    panel.border = element_rect(colour = "black", fill=NA, size=2)
  )+
  ylab(expression(Lp[r]~(m~s^-1~Mpa^-1))) + xlab(expression(Treatment))

参数说明 #

• 已删除geom层重复的x轴映射：全局ggplot()内已经定义过x轴映射规则，geom层重复书写属于冗余代码，不影响运行但没必要
• breaks：手动指定1e-9、1e-8、1e-7三个目标数量级作为刻度位置
• labels：用R原生表达式实现参考图的上标格式科学计数法刻度标签，和示例效果完全一致
• limits：给轴上下预留了10%~20%的边距，避免最高/最低值的误差线贴到面板边框，如果你的数据误差线超出当前范围，直接调整上下限数值即可
• 对数刻度会自动将三个数量级等间距排布，不需要额外安装第三方包、不需要做断轴处理，纯base ggplot2即可实现目标效果

内容的提问来源于stack exchange，提问作者Cesar Barrientos