在ggplot2分面分组条形图中设置同色系不同色调

现有代码 #

temp.data = data.frame (
  Species  = rep(c("A","B"),each=2, times=2),
  Status = rep(c("An","Bac"), times=4),
  Sex = rep(c("Male","Female"), each=4, times=1),
  Proportion = c(6.86, 7.65, 30.13, 35.71, 7.13, 10.33, 29.24, 31.09)
)

ggplot(temp.data, aes(x = Species, y = Proportion, fill = Status, alpha = Species)) +
  geom_bar(stat='identity', position = position_dodge(width = 0.73), width=.67) +
  facet_grid(Sex ~ .) + xlab("X title") + 
  ylab("Y title") + 
  scale_fill_manual(name = "Status", labels = c("An","Bac"),
                    values = c("#86a681","#0a3e03")) +
  scale_alpha_manual(values = c(0.6, 1)) +
  theme_light() + theme(
    legend.title= element_text(size = 8),
    legend.title.align=0.5,
    legend.position = c(),
    legend.background=element_blank(),
    legend.text=element_text(size=7),
    legend.key.size = unit(0.6, 'cm'),
    axis.title.x = element_text(size = 9),
    axis.title.y = element_text(size = 9),
    axis.title.y.right = element_text("Sex of groups"),
    strip.background = element_rect(
      color="lightgrey", fill="white", size=0.5, linetype="solid"),
    strip.text.y = element_text(color = "darkgrey", face = "bold")
  )

当前效果 #

每个Status对应固定颜色，通过透明度区分Species，呈现同色不同透明度的条形。

期望效果 #

每个Status下，不同Species对应同色系的不同深浅颜色（而非透明度差异），比如An组的A是浅绿、B是深绿，Bac组的A是更深的浅绿、B是最深的绿，保持同色系内的色调区分。

解决方案 #

核心思路是让fill映射到Status和Species的组合，为每个组合手动指定同色系颜色，替代透明度区分的方案。

修改后的代码 #

temp.data = data.frame (
  Species  = rep(c("A","B"),each=2, times=2),
  Status = rep(c("An","Bac"), times=4),
  Sex = rep(c("Male","Female"), each=4, times=1),
  Proportion = c(6.86, 7.65, 30.13, 35.71, 7.13, 10.33, 29.24, 31.09)
)

ggplot(temp.data, aes(x = Species, y = Proportion, fill = interaction(Status, Species))) +
  geom_bar(stat='identity', position = position_dodge(width = 0.73), width=.67) +
  facet_grid(Sex ~ .) + 
  xlab("X title") + 
  ylab("Y title") + 
  scale_fill_manual(
    name = "Status",
    labels = c("An (A)", "An (B)", "Bac (A)", "Bac (B)"),
    values = c("#b8d8b4", "#86a681", "#3a6b34", "#0a3e03") # 同色系渐变颜色
  ) +
  theme_light() + 
  theme(
    legend.title= element_text(size = 8),
    legend.title.align=0.5,
    legend.position = "right",
    legend.background=element_blank(),
    legend.text=element_text(size=7),
    legend.key.size = unit(0.6, 'cm'),
    axis.title.x = element_text(size = 9),
    axis.title.y = element_text(size = 9),
    axis.title.y.right = element_text("Sex of groups"),
    strip.background = element_rect(
      color="lightgrey", fill="white", size=0.5, linetype="solid"),
    strip.text.y = element_text(color = "darkgrey", face = "bold")
  )

关键修改说明 #

1. 填充映射调整：将fill从Status改为interaction(Status, Species)，让每个(Status, Species)组合对应独立的填充色。
2. 同色系颜色设置：在scale_fill_manual的values中，为每个组合指定同色系渐变颜色，确保同一Status下的Species颜色属于同一色系但深浅不同。
3. 移除透明度设置：不再需要alpha映射，直接用颜色深浅区分不同Species。

如果需要更规整的图例分组（比如按Status分组显示），可以额外使用guide_legend或ggnewscale包优化图例展示。

内容的提问来源于stack exchange，提问作者DSA