ggplot2 热图，带有范围值的颜色 [英] ggplot2 heatmap with colors for ranged values

问题描述

我想在 ggplot2 中制作热图.我的玩具数据和代码是:

I want to make a heatmap in ggplot2. My toy data and code is:

set.seed(12345)
dat <- 
  data.frame(
      Row = rep(x = LETTERS[1:5], times = 10)
    , Col = rep(x = LETTERS[1:10], each = 5)
    , Y = rnorm(n = 50, mean = 0, sd = 1)
    )
library(ggplot2)
p <- ggplot(data =  dat, aes(x = Row, y = Col)) + 
      geom_tile(aes(fill = Y), colour = "white") +
      scale_fill_gradient(low = "white", high = "steelblue")
p

我想要这样的范围值的配色方案:

I want to have color scheme for ranged values like this:

-3 <= Y < -2  ---> Dark Blue
-2 <= Y < -1  ---> Blue
-1 <= Y <  0  ---> Light Blue
 0 <= Y <  1  ---> Light Green
 1 <= Y <  2  ---> Green
 2 <= Y <= 3  ---> Dark Green

推荐答案

对于此类问题，您有多种选择，但这里只是一个起点.

You have several options for something like this, but here is one as a starting point.

首先，使用 cut 从 Y 创建一个具有适当范围的因子:

First, use cut to create a factor from Y with the appropriate ranges:

dat$Y1 <- cut(dat$Y,breaks = c(-Inf,-3:3,Inf),right = FALSE)

然后使用来自 RColorBrewer 的调色板进行绘图:

Then plot using a palette from RColorBrewer:

ggplot(data =  dat, aes(x = Row, y = Col)) + 
      geom_tile(aes(fill = Y1), colour = "white") +
      scale_fill_brewer(palette = "PRGn")

这种配色方案在低端比蓝色更紫色，但它是我在啤酒调色板中能找到的最接近的.

This color scheme is more purple than blue on the low end, but it's the closest I could find among the brewer palette's.

如果您想构建自己的，您可以简单地使用 scale_fill_manual 并为 values 参数指定所需的颜色向量.

If you wanted to build your own, you could simply use scale_fill_manual and specify your desired vector of colors for the values argument.

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