如何在 heatmap.2 (R) 中绘制不同且独立的颜色渐变图例

Question

我从计算中得到一个矩阵，其值在 0 到 4 之间。我使用函数 heatmap.2 进行绘图。

这个想法是在单元格值的函数中具有一个颜色代码和不同的渐变：

从 0 到 0.99：红色渐变

从 1 到 1.99：黄色渐变

从 2 到 2.99：绿色渐变

从 3 到 4：灰度渐变

如您所见，渐变不是独立的，颜色从一个范围平滑地变化到另一个范围（例如，我将橙色从红色变为黄色）。如何获得 4 个不同且独立的梯度？意思是，从0到0.99只有红色渐变，从1到1.99只有黄色渐变等

这是我使用的代码（我为示例创建了一个随机矩阵）：

library(gplots)

# create a matrix of random values from [0, 4]
random.matrix  <- matrix(runif(100, min = 0, max = 4), nrow = 10)

quantile.range <- quantile(random.matrix, probs = seq(0, 1))
palette.breaks <- seq(quantile.range["0%"], quantile.range["100%"], 0.25)
color.palette  <- colorRampPalette(c("red", "yellow", "green", "grey"))(length(palette.breaks)-1)
heatmap.2(
  random.matrix,
  dendrogram = "none",
  scale      = "none",
  trace      = "none",
  symbreaks=FALSE,
  symkey=FALSE, 
  key        = TRUE,
  key.title = 'class information',
  key.xlab = 'class number',
  keysize = 2,
  #( "bottom.margin", "left.margin", "top.margin", "right.margin" )
  key.par=list(mar=c(3,3.5,2,0)),
  labRow     = NA,
  labCol     = NA,
  col    = color.palette,
  breaks = palette.breaks,
)
legend(x="topright", legend=c("class 1: city", "class 2: crops", "class 3: forest", "class 4: road"),fill=c("red", "yellow", "green", "grey", ""))

剧情如下：

Answer 1

我是这样找到的：

# gplots contains the heatmap.2 function
library(gplots)

# create a matrix of random values from [0, 4]
random.matrix  <- matrix(runif(100, min = 0, max = 4), nrow = 10)

quantile.range <- quantile(random.matrix, probs = seq(0, 1))
palette.breaks <- seq(quantile.range["0%"], quantile.range["100%"], 0.25)

colfunc1 <- colorRampPalette(c("white", "red"))
colfunc2 <- colorRampPalette(c("white", "yellow"))
colfunc3 <- colorRampPalette(c("white", "green"))
colfunc4 <- colorRampPalette(c("grey", "black"))

color.palette  <- colorRampPalette(c(colfunc1(4), colfunc2(4), colfunc3(4), colfunc4(3)))(length(palette.breaks)-1)

heatmap.2(
  random.matrix,
  dendrogram = "none",
  scale      = "none",
  trace      = "none",
  symbreaks=FALSE,
  symkey=FALSE, 
  key        = TRUE,
  key.title = 'class information',
  key.xlab = 'class number',
  keysize = 2,
  #( "bottom.margin", "left.margin", "top.margin", "right.margin" )
  key.par=list(mar=c(3,3.5,2,0)),
  labRow     = NA,
  labCol     = NA,
  col    = color.palette,
  breaks = palette.breaks,
)
legend(x="topright", legend=c("class 1: city", "class 2: crops", "class 3: forest", "class 4: road"),fill=c("red", "yellow", "green", "grey", ""))