用额外的刻度和标签注释 ggplot [英] Annotate ggplot with an extra tick and label
问题描述
你能帮我注释一个 ggplot2 散点图吗?
典型的散点图(黑色):
df <- data.frame(x=seq(1:100), y=sort(rexp(100, 2), 递减 = T))ggplot(df, aes(x=x, y=y)) + geom_point()我想以额外的勾号和自定义标签(红色)的形式添加注释:
示例图片:
四种解决方案.
首先使用 scale_x_continuous 添加附加元素，然后使用 theme 自定义新文本和刻度线(加上一些额外的调整).
第二个使用 annotate_custom 来创建新的 grob:一个 text grob 和一个 line grob.Grob 的位置在数据坐标中.结果是，如果 y 轴的限制发生变化，grob 的定位将发生变化.因此，y 轴在下面的示例中是固定的.此外，annotation_custom 试图在绘图面板之外绘图.默认情况下，绘图面板的剪辑是打开的.它需要关闭.
第三个是第二个的变体(并借鉴了
第四种方案
更新到 ggplot2 v3.0.0
## 视口图书馆(ggplot2)图书馆(网格)df <- data.frame(x=seq(1:100), y=sort(rexp(100, 2), 递减 = T))(p = ggplot(df, aes(x=x, y=y)) + geom_point())# 使用正则表达式搜索绘图面板树 = as.character(current.vpTree())pos = gregexpr("\[panel.*?\]", 树)match = unlist(regmatches(Tree, pos))match = gsub("^\[(panel.*?)\]$", "\1", match) # 删除方括号向下视口(匹配)######## 或者自己找到绘图面板# current.vpTree() # 找到绘图面板# downViewport("panel.6-4-6-4")###### 获取 ggplot 的 x-scale 的限制，包括扩展.x.axis.limits = ggplot_build(p)$layout$panel_params[[1]][[["x.range"]]# 在绘图面板中设置单位，以便 x 轴单位实际上是原生"，# 但 y 轴单位实际上是npc".pushViewport(dataViewport(yscale = c(0, 1), xscale = x.axis.limits, clip = "off"))grid.text("xyz", x = 30, y = -.05, just = "center", gp = gpar(col = "red"), default.units = "native")grid.lines(x = 30, y = c(.02, -.02), gp = gpar(col = "red", lwd = 2), default.units = "native")向上视口(0)Can you help me annotate a ggplot2 scatterplot?
To a typical scatter plot (black):
df <- data.frame(x=seq(1:100), y=sort(rexp(100, 2), decreasing = T))
ggplot(df, aes(x=x, y=y)) + geom_point()
I want to add annotations in the form of an extra tick and a custom label (red):
Example image:
Four solutions.
The first uses scale_x_continuous to add the additional element then uses theme to customize the new text and tick mark (plus some additional tweaking).
The second uses annotate_custom to create new grobs: a text grob, and a line grob. The locations of the grobs are in data coordinates. A consequence is that the positioning of the grob will change if the limits of y-axis changes. Hence, the y-axis is fixed in the example below. Also, annotation_custom is attempting to plot outside the plot panel. By default, clipping of the plot panel is turned on. It needs to be turned off.
The third is a variation on the second (and draws on code from here). The default coordinate system for grobs is 'npc', so position the grobs vertically during the construction of the grobs. The positioning of the grobs using annotation_custom uses data coordinates, so position the grobs horizontally in annotation_custom. Thus, unlike the second solution, the positioning of the grobs in this solution is independent of the range of the y values.
The fourth uses viewports. It sets up a more convenient unit system for locating the text and tick mark. In the x direction, the location uses data coordinates; in the y direction, the location uses "npc" coordinates. Thus, in this solution too, the positioning of the grobs is independent of the range of the y values.
First Solution
## scale_x_continuous then adjust colour for additional element
## in the x-axis text and ticks
library(ggplot2)
df <- data.frame(x=seq(1:100), y=sort(rexp(100, 2), decreasing = T))
p = ggplot(df, aes(x=x, y=y)) + geom_point() +
scale_x_continuous(breaks = c(0,25,30,50,75,100), labels = c("0","25","xyz","50","75","100")) +
theme(axis.text.x = element_text(color = c("black", "black", "red", "black", "black", "black")),
axis.ticks.x = element_line(color = c("black", "black", "red", "black", "black", "black"),
size = c(.5,.5,1,.5,.5,.5)))
# y-axis to match x-axis
p = p + theme(axis.text.y = element_text(color = "black"),
axis.ticks.y = element_line(color = "black"))
# Remove the extra grid line
p = p + theme(panel.grid.minor = element_blank(),
panel.grid.major.x = element_line(color = c("white", "white", NA, "white", "white", "white")))
p
Second Solution
## annotation_custom then turn off clipping
library(ggplot2)
library(grid)
df <- data.frame(x=seq(1:100), y=sort(rexp(100, 2), decreasing = T))
p = ggplot(df, aes(x=x, y=y)) + geom_point() +
scale_y_continuous(limits = c(0, 4)) +
annotation_custom(textGrob("xyz", gp = gpar(col = "red")),
xmin=30, xmax=30,ymin=-.4, ymax=-.4) +
annotation_custom(segmentsGrob(gp = gpar(col = "red", lwd = 2)),
xmin=30, xmax=30,ymin=-.25, ymax=-.15)
g = ggplotGrob(p)
g$layout$clip[g$layout$name=="panel"] <- "off"
grid.draw(g)
Third Solution
library(ggplot2)
library(grid)
df <- data.frame(x=seq(1:100), y=sort(rexp(100, 2), decreasing = T))
p = ggplot(df, aes(x=x, y=y)) + geom_point()
gtext = textGrob("xyz", y = -.05, gp = gpar(col = "red"))
gline = linesGrob(y = c(-.02, .02), gp = gpar(col = "red", lwd = 2))
p = p + annotation_custom(gtext, xmin=30, xmax=30, ymin=-Inf, ymax=Inf) +
annotation_custom(gline, xmin=30, xmax=30, ymin=-Inf, ymax=Inf)
g = ggplotGrob(p)
g$layout$clip[g$layout$name=="panel"] <- "off"
grid.draw(g)
Fourth Solution
Updated to ggplot2 v3.0.0
## Viewports
library(ggplot2)
library(grid)
df <- data.frame(x=seq(1:100), y=sort(rexp(100, 2), decreasing = T))
(p = ggplot(df, aes(x=x, y=y)) + geom_point())
# Search for the plot panel using regular expressions
Tree = as.character(current.vpTree())
pos = gregexpr("\[panel.*?\]", Tree)
match = unlist(regmatches(Tree, pos))
match = gsub("^\[(panel.*?)\]$", "\1", match) # remove square brackets
downViewport(match)
#######
# Or find the plot panel yourself
# current.vpTree() # Find the plot panel
# downViewport("panel.6-4-6-4")
#####
# Get the limits of the ggplot's x-scale, including the expansion.
x.axis.limits = ggplot_build(p)$layout$panel_params[[1]][["x.range"]]
# Set up units in the plot panel so that the x-axis units are, in effect, "native",
# but y-axis units are, in effect, "npc".
pushViewport(dataViewport(yscale = c(0, 1), xscale = x.axis.limits, clip = "off"))
grid.text("xyz", x = 30, y = -.05, just = "center", gp = gpar(col = "red"), default.units = "native")
grid.lines(x = 30, y = c(.02, -.02), gp = gpar(col = "red", lwd = 2), default.units = "native")
upViewport(0)
这篇关于用额外的刻度和标签注释 ggplot的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
