控制ggplot2图例外观而不影响绘图 [英] Control ggplot2 legend look without affecting the plot

问题描述

我正在用 ggplot2 绘制线条，如下所示:

I'm plotting lines with ggplot2 like this:

ggplot(iris, aes(Petal.Width,Petal.Length,color=Species)) + geom_line() + theme_bw()

.

我发现图例标记很小，所以我希望它们更大.如果我改变大小，图上的线条也会改变:

I find legend marks to be small so I want them to be bigger. If I change the size, lines on the plot change too:

ggplot(iris, aes(Petal.Width,Petal.Length,color=Species)) + geom_line(size=4) + theme_bw()

.

但我只想在图例中看到粗线，我希望情节上的线很细.我尝试使用 legend.key.size 但它改变了标记的平方，而不是线的宽度:

But I only want to see thick lines in the legend, I want lines on the plot to be thin. I tried to use legend.key.size but it changes the square of the mark, not the width of the line:

library(grid)  # for unit
ggplot(iris,aes(Petal.Width,Petal.Length,color=Species))+geom_line()+theme_bw() + theme(legend.key.size=unit(1,"cm"))

我也尝试使用积分:

ggplot(iris,aes(Petal.Width,Petal.Length,color=Species)) + geom_line() + geom_point(size=4) + theme_bw()

但当然它仍然影响情节和传说:

But of course it still affects both plot and legend:

我想用线条表示情节，用点/点表示图例.

I wanted to use lines for the plot and dots/points for the legend.

所以我要问两件事:

1. 如何在不改变情节的情况下改变图例中的线宽?
2. 如何在图中画线，而在图例中画点/点/正方形?

推荐答案

要仅在图例中更改线宽，您应该使用函数 guides() 然后用于 colour= 使用 guide_legend() 和 override.aes= 并设置 size=.这将覆盖绘图中使用的大小，并将仅对图例使用新的大小值.

To change line width only in the legend you should use function guides() and then for colour= use guide_legend() with override.aes= and set size=. This will override size used in plot and will use new size value just for legend.

ggplot(iris,aes(Petal.Width,Petal.Length,color=Species))+geom_line()+theme_bw()+
       guides(colour = guide_legend(override.aes = list(size=3)))

要在图例中获取点和绘图解决方法中的线将添加 geom_point(size=0) 以确保点不可见，然后在 guides() 中设置 linetype=0 删除线和 size=3 以获得更大的点.

To get points in legend and lines in plot workaround would be add geom_point(size=0) to ensure that points are invisible and then in guides() set linetype=0 to remove lines and size=3 to get larger points.

ggplot(iris,aes(Petal.Width,Petal.Length,color=Species))+geom_line()+theme_bw()+
       geom_point(size=0)+
       guides(colour = guide_legend(override.aes = list(size=3,linetype=0)))

这篇关于控制ggplot2图例外观而不影响绘图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！