多层ggplot的自定义图例 [英] Custom legend for multiple layer ggplot

问题描述

我正在尝试为 ggplot 获取自定义图例，其中数据来自两个单独的数据框.请参阅下面的最小可重现示例.

I'm trying to get a custom legend for a ggplot with data coming from two separate data frames. See below for a minimum reproducible example.

我想要完成的是有一个描述色带填充、黑线和红线的图例.

What I'm trying to accomplish is to have a legend describing the ribbon fill, the black line, and the red line.

require(ggplot2)
x=seq(1,10,length=100)
data=data.frame(x,dnorm(x,mean=6.5,sd=1))
names(data)=c('x','new.data')
x.ribbon=seq(1,10,length=20)
ribbon=data.frame(x.ribbon,
                  dnorm(x.ribbon,mean=5,sd=1)+.01,
                  dnorm(x.ribbon,mean=5,sd=1)-.01,
                  dnorm(x.ribbon,mean=5,sd=1))
names(ribbon)=c('x.ribbon','max','min','avg')
ggplot()+geom_ribbon(data=ribbon,aes(ymin=min,ymax=max,x=x.ribbon),fill='lightgreen')+
  geom_line(data=ribbon,aes(x=x.ribbon,y=avg),color='black')+
  geom_line(data=data,aes(x=x,y=new.data),color='red')+
  xlab('x')+ylab('density')

推荐答案

不是设置 colour 和 fill，而是使用几何美学映射它们>aes 然后使用 scale_xxx_manual 或 scale_xxx_identity.

Instead of setting colour and fill, map them using the geometry aesthetics aes and then use scale_xxx_manual or scale_xxx_identity.

例如

ggplot()+geom_ribbon(data=ribbon,aes(ymin=min,ymax=max,x=x.ribbon,fill='lightgreen'))+
    geom_line(data=ribbon,aes(x=x.ribbon,y=avg,color='black'))+
    geom_line(data=data,aes(x=x,y=new.data,color='red'))+
    xlab('x')+ylab('density') + 
    scale_fill_identity(name = 'the fill', guide = 'legend',labels = c('m1')) +
    scale_colour_manual(name = 'the colour', 
         values =c('black'='black','red'='red'), labels = c('c2','c1'))

请注意，您必须指定 guide = 'legend' 以强制 scale_..._identity 生成图例.

Note that you must specify guide = 'legend' to force scale_..._identity to produce a legend.

scale_...manual 您可以为值传递一个命名向量——名称应该是您在调用 geom_... 时调用的颜色然后你可以很好地标记.

scale_...manual you can pass a named vector for the values -- the names should be what you called the colours within the calls to geom_... and then you can label nicely.

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