如何使用 ggplot2 在 y 截距(y 轴)上添加一个点

How to add a point on the y-intercept (y-axis) using ggplot2

我有一个散点图,其中 y 轴比例在特定点发生变化,以绘制具有某些极值的数据。我正在尝试在 y 轴上添加某种视觉提示,指示缩放在该点发生变化。

这是一个情节示例

library(scales)
library(ggplot2)

set.seed(104)

ggdata <- data.frame('x' = rep('a',100),
                     'y' = c(runif(90, 0, 20), runif(10, 90, 100)))

transformation <- trans_new(
  "my_transformation", 
  transform = function(x) ifelse(x <= 30, x / 5, (x - 30) / 20 + 30 / 5),
  inverse = function(x) ifelse(x <= 30 / 5, x * 5, (x - 30 / 5) * 20 + 30)
)

ggplot(data = ggdata) + 
  geom_jitter(aes(x = x, y = y)) +
  scale_y_continuous(trans = transformation, breaks = c(0, 10, 20, 30, 50, 70, 90, 110))  

我想在 y 轴上向 "tick 30" 添加一些标记以进行缩放。

我想在轴上加一个双刻度,但是没有linetype看起来像双线。该产品应类似于 this。我知道像 scale_y_log10 这样的转换,但我更愿意使用随数据动态变化的自定义缩放。

编辑:根据@Tjebo 的建议,我使用 annotate 将“=”添加到 y 轴断点:

library(scales)
library(ggplot2)

set.seed(104)

ggdata <- data.frame('x' = rep('a',100),
                     'y' = c(runif(90, 0, 20), runif(10, 90, 100)))

transformation <- trans_new(
  "my_transformation", 
  transform = function(x) ifelse(x <= 30, x / 5, (x - 30) / 20 + 30 / 5),
  inverse = function(x) ifelse(x <= 30 / 5, x * 5, (x - 30 / 5) * 20 + 30)
)

mybreaks <- c(0, 10, 20, 30, 50, 70, 90, 110)
tick_linetype <- rep("solid", length(mybreaks))
tick_linetype[4] <- "blank"

ggplot(data = ggdata) + 
  geom_jitter(aes(x = x, y = y)) +
  annotate(geom = "point", shape = "=", x = -Inf, y = 30, size = 3) +
  scale_y_continuous(trans = transformation, breaks = mybreaks) +
  theme(axis.ticks.y = element_line(linetype = tick_linetype)) + 
  coord_cartesian(clip = 'off')

我无法得到您链接到的确切外观,但也许其中一些想法对您有用。

您可以将您指定的值设置为次要中断,并只为次要中断添加一行(这里我无法选择 20 的确切值,因为那已经是一个主要中断,但也许您可以尝试用数字得到你喜欢的东西):

ggplot(data = ggdata) + 
  geom_jitter(aes(x = x, y = y)) +
  scale_y_continuous(trans = transformation, minor_breaks=20.05,breaks = c(0, 10,20, 30, 50, 70, 90, 110))+
  theme(
    panel.grid.minor.y = element_line(1)
  )

另一种选择是自行更改标签。在这里,我将值 20 加粗并包裹在 () 中,但您也可以添加其他符号:

ggplot(data = ggdata) + 
  geom_jitter(aes(x = x, y = y)) +
  scale_y_continuous(trans = transformation, minor_breaks = c(0, 10, 20, 30, 50, 70, 90, 110),
                       breaks  = c(0, 10, 20, 30, 50, 70, 90, 110), labels=c(0, 10, expression(bold(("20"))), 30, 50, 70, 90, 110))

您可以在绘图中添加一个片段,这不是最好的选择,因为 x 轴不是连续的,但也许它会激发灵感:

ggplot(data = ggdata) + 
  geom_jitter(aes(x = x, y = y)) +
  scale_y_continuous(trans = transformation, breaks = c(0, 10, 20, 30, 50, 70, 90, 110))+
  geom_segment(aes(x=-.01,y=19.5,xend=.01,yend=20.5),size=1.5)

也许您也可以只遮蔽绘图的底部(或顶部)部分:

ggplot(data = ggdata,aes(x = x, y = y)) + 
  geom_jitter() +
  scale_y_continuous(trans = transformation,breaks = c(0, 10,20, 30, 50, 70, 90, 110))+
  annotate("rect", xmin = .4, xmax = 1.6, ymin = 0, ymax = 21,
           alpha = .2)

I was thinking of adding a double tick on the axis, but there is no linetype that looks like a double line.

您可以使用任何字符作为点形。也可以是等号或反斜杠等。

例如:

library(scales)
library(ggplot2)

set.seed(104)

ggdata <- data.frame('x' = rep('a',100),
                     'y' = c(runif(90, 0, 20), runif(10, 90, 100)))

transformation <- trans_new(
  "my_transformation", 
  transform = function(x) ifelse(x <= 30, x / 5, (x - 30) / 20 + 30 / 5),
  inverse = function(x) ifelse(x <= 30 / 5, x * 5, (x - 30 / 5) * 20 + 30)
)

ggplot(data = ggdata) + 
  geom_jitter(aes(x = x, y = y)) +
  annotate(geom = "point", shape = "=", x = -Inf, y = 30, size = 8, color = 'red') +
  scale_y_continuous(trans = transformation, breaks = c(0, 10, 20, 30, 50, 70, 90, 110))+
  coord_cartesian(clip = 'off')

我删除了剪辑,但你也可以保留它。颜色只是为了突出显示而选择的。

或者,更好的是,使用文本注释。然后你也可以改变角度 - 有点不错。

ggplot(data = ggdata) +
  geom_jitter(aes(x = x, y = y)) +
  annotate(geom = "text", label = "=", x = -Inf, y = 30, size = 8, color = "red", angle = 45) +
  scale_y_continuous(trans = transformation, breaks = c(0, 10, 20, 30, 50, 70, 90, 110)) +
  coord_cartesian(clip = "off")

reprex package (v0.3.0)

于 2020-04-21 创建

此解决方案应该可以帮助您了解轴的外观。 FWIW 我想警告不要打破轴,除非你明确告诉你的听众他们。在下面的代码中,我创建了两个图,一个用于 30 以下的数据,另一个数据用于极值点(并删除其 x 轴和标签)。然后我使用 plot.margin 来设置图边距,这样当我把它们放在 grid.arrange 中时它们会重叠一点。您可能不得不弄乱边距以使标签对齐。

library(scales)
library(ggplot2)
library(gridExtra)
set.seed(104)

ggdata <- data.frame('x' = rep('a',100),
                     'y' = c(runif(90, 0, 20), runif(10, 90, 100)))

p1 <- ggplot(data = ggdata) + 
  geom_jitter(aes(x = x, y = y)) +
  scale_y_continuous(breaks = seq(0,30,5), limits = c(0,30))+
  theme(plot.margin=unit(c(0,.83,0,1), "cm")) 




p2 <- ggplot(data = ggdata) + 
  geom_jitter(aes(x = x, y = y)) +
  scale_y_continuous( breaks = seq(60,100,10), limits = c(60,100)) +
  scale_x_discrete()+
  theme(axis.title.x=element_blank(),
        axis.text.x=element_blank(),
        axis.ticks.x=element_blank(),
        plot.margin=unit(c(0,1,-0.1,1), "cm"))


grid.arrange(p2,p1)