在R中設置自定義色標

Question

我正在嘗試在R中設置自定義比例。我的數據范圍從-5.4到+3.6，我想將數據居中於0（白色）。 我希望對數據進行縮放，使得我在0以上和以下具有相同數量的漸變（我現在正在拍攝7個）。 我遇到的問題是我無法正確縮放，我不確定我的問題在哪里。

我的代碼（源數據在底部的Pastebin鏈接中）：

   png('127-2_4_compare_other.png',width = 1200, height = 800, units = "px")
   colfunc <- colorRampPalette(c("blue", "white", "red"))
   f <- function(m) t(m)[,nrow(m):1]
   colorBarz=matrix(seq(-5.5,4,len=15),nrow=1)
   colorBarx=1
   source("127-2_4.CompareMatrix.txt")
   colorBary=seq(-5.4,3.6,len=15)
   cus_breaks=c(-5.400, -4.725, -4.050, -3.375, -2.700, -2.025, -1.350, -0.675,  0.45, 0.90, 1.35, 1.80, 2.25, 2.70, 3.15, 3.60)
   layout(matrix(c(1,2), 1, 2, byrow = TRUE), widths=c(9,1))
   image(f(Compare2and4),axes=FALSE,ylab="Amino acids",xlab="Position",main="Sample 2 vs. 4",col=colfunc(15),breaks=cus_breaks)
   axis(1, seq(from = 0, to = 1, by = 0.03703), labels=c(1:11,1:17))
   axis(2, seq(from = 0, to = 1, by = 0.0526),labels=rev(c("A","R","N","D","C","E","Q","G","H","I","L","K","M","F","P","S","T","W","Y","V")),las=2)
   image(colorBarx,colorBary,colorBarz,col=colfunc(15),axes=FALSE,xlab="",ylab="log(Sample4 / Sample2)",breaks=cus_breaks)
   axis(2,las=2)
   dev.off()

我正在尋找0到3.6之間的7個均勻分割的箱子和0到-5.4以下的7個均勻分開的箱子，我想要在白色箱子的中間點擊0。 此外，如果任何人都可以查看熱圖代碼本身，以確保沒有明顯的錯誤，我會非常感激。 源數據的Pastebin

Answer 1

您提出的色標的一個問題是，刻度上每個點之間的感知距離不相等。 與負端相比，相同的顏色距離是指正端的更大范圍的數據值。 我建議不要重新發明輪子，並利用ggplot的強大功能。

默認情況下，發散色標將為白色，中間值為0。

例如：

Compare2and4_t <- t(Compare2and4)[,nrow(Compare2and4):1]
am_ac <- c("A","R","N","D","C","E","Q","G","H","I","L","K","M","F","P","S","T","W","Y","V")
pdat <- data.frame(x = 1:nrow(Compare2and4_t), 
                   y = factor(rep(am_ac, each = nrow(Compare2and4_t)), levels = rev(am_ac)),
                   val = c(Compare2and4_t))

library(ggplot2)
library(scales)

ggplot(pdat, aes(x, y, fill = val)) + 
  geom_tile() +
  scale_fill_gradient2(low = 'darkblue', high = 'darkred', 
                       limits = c(-5.4, 3.6), oob = squish) +
  coord_equal(expand = FALSE) +
  scale_x_continuous(breaks = unique(pdat$x)) +
  theme_classic() +
  labs(x = 'Position', y = 'Amino acids')