如何反转绘图上的 y 轴 [英] How to invert the y-axis on a plot

问题描述

我想知道如何在 R 中绘制 y 轴反转的图，以便绘制的数据出现在第四象限(中的小日志刻度函数:

minor.ticks.axis <- function(ax,n,t.ratio=0.5,mn,mx,...){lims <- par("usr")if(ax %in%c(1,3)) lims <- lims[1:2] else lims[3:4]Major.ticks <- 漂亮(lims，n=5)if(missing(mn)) mn <- min(major.ticks)if(missing(mx)) mx <- max(major.ticks)major.ticks <- major.ticks[major.ticks >= mn &Major.ticks <= mx]标签 <- sapply(major.ticks,function(i)as.expression(bquote(10^ .(i))))轴(ax,at=major.ticks,labels=labels,...)n <- n+2未成年人 <- log10(pretty(10^major.ticks[1:2],n))-major.ticks[1]未成年人 <- 未成年人[-c(1,n)]minor.ticks = c(outer(minors,major.ticks,`+`))minor.ticks <- minor.ticks[minor.ticks >和小滴答声

制作一些可重现的示例数据:

x <- 1:8y <- 10^(sort(runif(8, 1, 10), 递减 = TRUE))

没有轴的绘图:

plot(x, log10(y), # 绘图函数xlab="", # 抑制 x 个标签type = 'l', # 指定折线图xlim = c(min(x), (max(x)*1.3)), # 扩展轴限制为文本注释留出空间ylim = c(0, max(log10(y))), # 同上轴 = FALSE) # 抑制两个轴

添加花哨的对数轴并将刻度标签向右旋转(感谢@joran！):

minor.ticks.axis(2, 9, mn=0, mx=10, las=1)

在顶部添加 x 轴:

轴(3)

添加 x 轴标签(感谢提示，@WojciechSobala)

mtext("x", side = 3, line = 2)

并在行尾添加注释

text(max(x), min(log10(y)), "示例", pos = 1)

结果如下:

I would like to know how to make a plot in R where the y-axis is inverted such that the plotted data appears in what would be the fourth quadrant (IV) of a cartesian plane, as opposed to the first (I) quadrant.

For reference, the plot I am trying to make looks very similar to the following (source):

I have found a number of questions online pertaining to reversing the numbering on the y-axis, but these all still plot the data in the first quadrant. Can anyone suggest how I might produce a plot similar to that shown above?

解决方案

Just to provide a worked out answer, following the comments of @timriffe and @joran...

Use the function for minor log ticks from this answer:

minor.ticks.axis <- function(ax,n,t.ratio=0.5,mn,mx,...){

  lims <- par("usr")
  if(ax %in%c(1,3)) lims <- lims[1:2] else lims[3:4]

  major.ticks <- pretty(lims,n=5)
  if(missing(mn)) mn <- min(major.ticks)
  if(missing(mx)) mx <- max(major.ticks)

  major.ticks <- major.ticks[major.ticks >= mn & major.ticks <= mx]

  labels <- sapply(major.ticks,function(i)
    as.expression(bquote(10^ .(i)))
                   )
  axis(ax,at=major.ticks,labels=labels,...)

  n <- n+2
  minors <- log10(pretty(10^major.ticks[1:2],n))-major.ticks[1]
  minors <- minors[-c(1,n)]

  minor.ticks = c(outer(minors,major.ticks,`+`))
  minor.ticks <- minor.ticks[minor.ticks > mn & minor.ticks < mx]


  axis(ax,at=minor.ticks,tcl=par("tcl")*t.ratio,labels=FALSE)

}

Make some reproducible example data:

x <- 1:8
y <- 10^(sort(runif(8, 1, 10), decreasing = TRUE))

Plot without axes:

plot(x, log10(y), # function to plot
xlab="",          # suppress x labels
type = 'l',       # specify line graph
xlim = c(min(x), (max(x)*1.3)),  # extend axis limits to give space for text annotation
ylim = c(0, max(log10(y))),      # ditto
axes = FALSE)    # suppress both axes

Add fancy log axis and turn tick labels right way up (thanks @joran!):

minor.ticks.axis(2, 9, mn=0, mx=10, las=1)

Add x-axis up the top:

axis(3)

Add x-axis label (thanks for the tip, @WojciechSobala)

mtext("x", side = 3, line = 2)

And add an annotation to the end of the line

text(max(x), min(log10(y)), "Example", pos = 1)

Here's the result:

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