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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()
