ggplot2: 添加辅助线

在ggplot2画图后，在图中添加辅助线

1. geom_hline() & geom_vline()

1.1 添加横向辅助线

plot()+geom_hline(aes(yintercept = 200), colour="blue", linetype="dashed")

ggplot()+geom_bar(data=kk, aes(x=aa, y=bb), col="gray", stat = "identity")+
  geom_bar(data=hh, aes(x=aa, y=bb), col="blue", stat = "identity")+
  geom_hline(aes(yintercept=200), colour="blue", linetype="dashed")  '#添加横向辅助线，示例一

示例一

1.2 添加纵向辅助线

plot()+geom_vline(aes(xintercept = 200), colour="blue", linetype="dashed")

ggplot()+geom_bar(data=kk, aes(x=aa, y=bb), col="gray", stat = "identity")+
  geom_bar(data=hh, aes(x=aa, y=bb), col="blue", stat = "identity")+
  geom_vline(aes(xintercept=2500), colour="red", linetype="dashed")  '#添加横向辅助线，示例二

示例二

2. geom_abline()

plot()+geom_abline(intercept=, slope=, col=, linetype="dashed")

intercept: 截距
slope: 斜率

ggplot()+geom_bar(data=kk, aes(x=aa, y=bb), col="gray", stat = "identity")+
  geom_bar(data=hh, aes(x=aa, y=bb), col="blue", stat = "identity")+
  geom_abline(intercept=400, slope=-7.447e-02, colour="red", linetype="dashed")  '#添加具有倾斜角度的辅助线，可以用来画点图拟合出来的直线，示例三

示例三

geom_segment(aes(x = 0, xend = up_cutoff, y = down_cutoff, yend = down_cutoff),colour = "blue", linetype = "dashed", size = 0.8): 添加横向辅助线，限制长度

geom_segment(aes(x = up_cutoff, xend = up_cutoff, y = 0, yend = down_cutoff),colour = "blue", linetype = "dashed", size = 0.8): 添加纵向辅助线，限制长度