如何在 R 的图中为不同的值设置多个中断？

Question

我已经尝试了几个选项，但我无法使其工作，我想在图中表示一个矩阵的值。

我试图用某些颜色表示不同的值，其余的用渐变调色板表示。

数值与颜色的对应关系为：

• 红色：-2

• 绿色：-1

• 黑色：-0.7

• 蓝色：-0.5

• “YlOrRd”调色板：0-inf

这是我试过的代码，我不知道我做错了什么，但我只能用热调色板显示所有值。

y1<-c(-2,-1,-0.7,0.5,-2)
y2<-rep(-0.7,5)
y3<-seq(1,500,by=100)
y4<-rep(250,5)
y5<-seq(60,100,by=10)
heat<-rbind(y1,y2,y3,y4,y5)

bk = seq(-2, max(heat), length.out = 5)
color1 <- colorpanel(sum(bk[-1]<=-1.1), "red","red")
color2 <- colorpanel(sum(bk[-1]>-1.1 & bk[-1]<=-0.9), "green", "green") 
color3 <- colorpanel(sum(bk[-1]>-0.9 & bk[-1]<=-0.6), "black","black")
color4 <- colorpanel(sum(bk[-1]>-0.6 & bk[-1]<=-0.4), "blue", "blue")
color5 <- colorpanel(sum(bk[-1]>-0.4), "yellow","red")
colors <- c(color1,color2,color3,color4,color5)

image(t(apply(heat, 2, rev)),col=colors)

如果有人能帮我解决这个问题，我将不胜感激。

Answer 1

如果您对所有颜色进行硬编码，则可以使用 image() 来实现（也许有一种更优雅的方式，我不知道）。

grad <- colorRampPalette(c("#ffffb2", "#fd8d3c", "#bd0026"))
cols <- grad(max(round(h5$val))+1)
cols_val <- rep(NA, length(heat$val))
cols_val[which(heat$val >=0)] <- cols[round(heat$val[which(heat$val >=0)])+1]
cols_val[which(heat$val == -2)] <- "red"
cols_val[which(heat$val == -1)] <- "green"
cols_val[which(heat$val == -.7)] <- "black"
cols_val[which(heat$val == -.5)] <- "blue"

brk <- c(-2.5, -1.5, -.75, -.25, seq(0,410, by=10))
image(t(heat), breaks=brk, col = c("red", "green", "black", "blue", grad(41)))

但是，您可以使用 ggplot() 稍微优雅地完成此操作 [另外，我假设您希望 y1 的第四个元素为 b -0.5]：

heat <- t(heat) %>% as_tibble %>% 
  mutate(obs = 1:n()) %>% 
  pivot_longer(-obs, names_to="y", values_to="val") %>% 
  mutate(y = factor(y, levels=c("y1", "y2", "y3", "y4", "y5")) )
h1 <- heat %>% filter(val == -2)
h2 <- heat %>% filter(val == -1)
h3 <- heat %>% filter(val == -.7)
h4 <- heat %>% filter(val == -.5)
h5 <- heat %>% filter(val >= 0)

ggplot() + 
  geom_tile(data=h1, aes(x=obs, y=y), fill="red", width=1) + 
  geom_tile(data=h2, aes(x=obs, y=y), fill="green") + 
  geom_tile(data=h3, aes(x=obs, y=y), fill="black") + 
  geom_tile(data=h4, aes(x=obs, y=y), fill="blue") + 
  geom_tile(data=h5, aes(x=obs, y=y, fill=val)) + 
  scale_fill_gradientn(colors=c("#ffffb2", "#fd8d3c", "#bd0026")) + 
  geom_text(data=heat, aes(x=obs, y=y, label=val), col="gray60") + 
  theme_classic() + 
  labs(x="Observation", y="")