Annotating/labelling 个地块中的区域

Question

我有以下图表：

图表（红色字母除外）由以下代码生成：

boundary12 <- c(0.01, 0.005, 0.002, 0.001)
boundary23 <- c(0.1, 0.05, 0.02, 0.01)
boundary34 <- c(0.5, 0.6, 0.7, 0.55)

plot(boundary12, type="lines", ylim=c(0,1), xlab="Pollution level", ylab="Probability of event")
lines(boundary23)
lines(boundary34)

问题：

1）如果我生成很多图，有什么方法可以半自动把红色字母放进去吗？

2) 有没有办法给区域着色，例如区域1是蓝色，区域2是黄色，区域3是绿色？

Answer 1

这是使用多边形函数执行填充的解决方案。这将需要扩展以获得更通用的解决方案来处理更多点和可变上限。

boundary12 <- c(0.01, 0.005, 0.002, 0.001)
boundary23 <- c(0.1, 0.05, 0.02, 0.01)
boundary34 <- c(0.5, 0.6, 0.7, 0.55)

plot(boundary12, type="lines", ylim=c(0,1), xlab="Pollution level", ylab="Probability of event")
lines(boundary23)
lines(boundary34)
#create polygons and fill
polygon(x=c(1:4, 4:1), y=c(boundary12, rev(boundary23)), col="blue")
polygon(x=c(1:4, 4:1), y=c(boundary23, rev(boundary34)), col="yellow")
polygon(x=c(1:4, 4,1 ), y=c(boundary34, c(1,1)), col="green")

Answer 2

可以通过计算多边形质心自动放置注释。

plot(boundary12, type="n", ylim=c(0,1), xlab="Pollution level",
  ylab="Probability of event")

poly12 <- data.frame(x=c(1:4, 4:1), y=c(boundary12, rev(boundary23)))
poly23 <- data.frame(x=c(1:4, 4:1), y=c(boundary23, rev(boundary34)))
poly34 <- data.frame(x=c(1:4, 4:1), y=c(boundary34, rep(1, 4)))

polygon(poly12, border="#00000066", col="skyblue")
polygon(poly23, border="#00000066", col="gold")
polygon(poly34, border="#00000066", col="darkolivegreen3")

library(maps)
centroid <- maps:::centroid.polygon

p12 <- centroid(poly12)
p23 <- centroid(poly23)
p34 <- centroid(poly34)

textcoor <- rbind(p12, p23, p34)
textcoor[1, 1] <- textcoor[1 ,1] * 0.8 # to smooch nr1 a bit to the left

text(textcoor, labels=1:3, col="darkblue", cex=1.2)

Annotating/labelling 个地块中的区域

Annotating/labelling areas in a plot

plot

r

polygon