ggplot2-annotation|画图点“精”，让图自己“解释”
可视化的展示方式可以使数据更易读，且容易看出一些数据下隐藏的“结果”，而添加注释则可以进一步聚焦到想重点展示的“信息”。
一 绘制基础图
library(ggplot2)
p <- ggplot(mtcars, aes(x = wt, y = mpg)) +
geom_point()更多参数ggplot2|详解八大基本绘图要素，主题ggplot2|theme主题设置，详解绘图优化-“精雕细琢”，图例ggplot2 |legend参数设置，图形精雕细琢 可参考。
二 添加“注释”
2.1 添加文字标签
1) 通过x y 指定标签的位置
p + annotate("text", x = 4, y = 25, label = "add text",
color="orange",size = 5, angle=45, fontface="bold" )2) 生成注释数据集，然后添加
annotation <- data.frame(
x = c(2,4),
y = c(20,25),
label = c("label 1", "label 2")
)A：geom_text方式添加
p + geom_text(data=annotation, aes( x=x, y=y, label=label))B：geom_label方式添加
p + geom_label(data=annotation, aes( x=x, y=y, label=label),
color="blue", size=5 , angle= 60, fontface="bold" )如果待注释的text太多，可使用ggrepel包解决标签太多导致的重叠问题
2.2 点注释
1）添加点
p + annotate(geom = "point", x = 4, y = 25, colour = "orange", size = 5)2）更改原有点
对齐数据集中数据坐标即可
p + annotate(geom = "point", x = 2.620, y = 21.0, colour = "red", size = 5)3）想在原有点外加一个圈，怎么办呢？
p +
annotate(geom = "point", x = 2.620, y = 21.0, colour = "red", size = 3) +
annotate(geom = "point", x = 2.620, y = 21.0)额，，我想到的是图层叠加，有其他办法的欢迎告知
。
4）pointrange添加点及range
p + annotate("pointrange", x = 3.5, y = 20, ymin = 12, ymax = 28,
colour = "orange", size = 1.5, alpha=0.6)2.3 线 , 矩形注释
1） 添加矩形，给出边的范围
p + annotate("rect", xmin=2, xmax=3, ymin=20 , ymax=30,
alpha=0.2, color="blue", fill="blue")2）添加线段，给出两端点位置
p + annotate("segment", x = 1, xend = 3, y = 25, yend = 15,
colour = "purple", size=3, alpha=0.6)3）线段加箭头，给出两端点位置
p + annotate("segment", x = 2, xend = 4, y = 15, yend = 25,
colour = "pink", size=3, alpha=0.6,
arrow=arrow())曲线加箭头？
p + annotate("curve", x = 4, xend = 2.620, y = 30, yend = 21.0,
colour = "blue", curvature = .3, arrow = arrow(length = unit(2, "mm"))
) + annotate(geom = "text", x = 4.1, y = 30.1, label = "关注这个点？", hjust = "left")2.4 添加垂直线
p + geom_hline(yintercept=25, color="orange", size=1) + geom_vline(xintercept=3, color="orange", size=1)2.5 添加轮廓图
library(ggforce)
library(concaveman)
ggplot(mpg, aes(displ, hwy,col = cyl)) +
geom_point() + geom_mark_hull(aes(label = cyl, group = cyl),
show.legend = FALSE, expand = unit(3, "mm")) +
theme_no_axes()举报
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