图例太多时，会挤压正图，显得正图展示区域很小，这时有必要缩小图例。
################# # 减小ggplot图例 ################# library(ggplot2) p <- ggplot(mtcars, aes(drat, mpg, color = factor(gear), shape = factor(vs))) + geom_point(size = 2) + theme_classic() + theme(legend.position = c(0.1, 0.7)) p # Overwrite given size (2) to 0.5 (super small) p <- p + guides(shape = guide_legend(override.aes = list(size = 0.5))) p p <- p + guides(color = guide_legend(override.aes = list(size = 0.5))) p p <- p + theme(legend.title = element_text(size = 3), legend.text = element_text(size = 3)) p addSmallLegend <- function(myPlot, pointSize = 0.5, textSize = 3, spaceLegend = 0.1) { myPlot + guides(shape = guide_legend(override.aes = list(size = pointSize)), color = guide_legend(override.aes = list(size = pointSize))) + theme(legend.title = element_text(size = textSize), legend.text = element_text(size = textSize), legend.key.size = unit(spaceLegend, "lines")) } # Apply on original plot addSmallLegend(p) ################## # 折叠图例文本 ################## a <- (1:10) b <- c(1,1.5,2,4,5,5.3,7,9,9.5,9.8) places = c("Birmingham","Chester-le-street","Cambridge", "Newcastle-upon-Tyne","Peterborough","Cambridge", "Newcastle-upon-Tyne","Peterborough","Liverpool","Stratford-upon-Avon") df1 = data.frame(a,b,places) library(ggplot2) p <- ggplot(df1, aes(x=a, y=b)) + geom_point(aes(colour = places), size=3) p #指定图例列数 library(scales) p + guides(colour = guide_legend(nrow = 2)) p ##或换行 df1$places<-sub("-", "- \n ", df1$places) p = ggplot(df1, aes(x=a, y=b)) + geom_point(aes(colour = places), size=3) p
来源：博客园
作者：小xuo生
链接：https://www.cnblogs.com/jessepeng/p/11454520.html