更改ggplot2中图例中的键标签

Question

我尝试更改ggplot上的键标签，但未成功。当我在scale_color_manual行指示标签时，图例看起来是重复的。我的错误在哪里？

考虑示例：

mydata <- data.frame(
year=as.integer(rep(2010:2020,each=2)),
type=rep(c("a","b"),11),
value=c(617,186,546,241,430,217,349,188,286,141,446,166,442,167,424,210,421,182,405,190,432,194))

ggplot(mydata,aes(year,value,group=type))+
    theme_bw()+
    theme(
        axis.text=element_text(size=16),
        axis.title=element_text(size=18),
        legend.position=c(.75,.885),
        legend.key = element_rect(color = "white", fill = NA),
        legend.key.size = unit(1, "cm"),
        legend.title=element_blank(),
        legend.text=element_text(size=20)
    )+
    labs(x="year",y="number")+
    geom_point(aes(color=type,shape=type),size=3)+
    scale_x_continuous(breaks = seq(min(mydata$year),max(mydata$year), by = 2))+
    scale_shape_manual(values=c(15,19))+
    scale_color_manual(values=c("red","blue"))

但是如果我将图例键“ a”和“ b”分别替换为“ a组”和“ b组”，则

scale_color_manual(values=c("red","blue"),labels=c("group a","group b"))

我得到了重复的图例，而彩色的子弹也弄错了。

wrong plot

怎么了？

谢谢！

Answer 1

此问题是由更改颜色标签而不是形状标签引起的。因此，您需要在图形和颜色上应用标签，或者在绘制之前更改type因素标签。

library(ggplot2)
library(dplyr)

mydata %>%
  mutate(type = factor(type, labels = c("group a","group b"))) %>%
  ggplot(aes(year,value))+
  theme_bw()+
  theme(
    axis.text=element_text(size=16),
    axis.title=element_text(size=18),
    legend.position=c(.75,.885),
    legend.key = element_rect(color = "white", fill = NA),
    legend.key.size = unit(1, "cm"),
    legend.title=element_blank(),
    legend.text=element_text(size=20)
  )+
  labs(x="year",y="number")+
  geom_point(aes(color=type,shape=type),size=3)+
  scale_x_continuous(breaks = seq(min(mydata$year),max(mydata$year), by = 2))+
  scale_shape_manual(values=c(15,19))+
  scale_color_manual(values=c("red","blue"))

Answer 2

只要在颜色和形状比例上添加相同的标签，就可以在不更改因子水平的情况下执行此操作：

ggplot(mydata,aes(year,value,group=type))+
    theme_bw()+
    theme(
        axis.text=element_text(size=16),
        axis.title=element_text(size=18),
        legend.position=c(.75,.885),
        legend.key = element_rect(color = "white", fill = NA),
        legend.key.size = unit(1, "cm"),
        legend.title=element_blank(),
        legend.text=element_text(size=20)
    )+
    labs(x="year",y="number")+
    geom_point(aes(color=type,shape=type),size=3)+
    scale_x_continuous(breaks = seq(min(mydata$year),max(mydata$year), by = 2))+
    scale_shape_manual(values=c(15,19), labels = c("group a", "group b")) +
    scale_color_manual(values=c("red","blue"), labels = c("group a", "group b"))