r - 在图例中分离 geom_point 和 geom_line

Question

我有一个叠加了列和点的数据集。绘图相当简单，但我似乎无法让 geom_point 显示为单独的图例。相反，它默认将两者结合起来。

我尝试将这些点添加为单独的数据框，将映射点添加为因子，以及在论坛上找到无穷无尽的功能。有什么提示吗？

下面的简化示例：

library(ggplot2)
Site <- c("A", "B", "C", "A", "B", "C")
Year <- c(2020, 2020, 2020, 2019, 2019, 2019)
Geomean <- c(65,184,27,21,67,51)
Historical.Geomean <- c(76,81,44,76,81,44)

df <- data.frame(Site, Year, Geomean, Historical.Geomean)

df$Year <- as.factor(df$Year)

fw_ecoli_plot <-
  ggplot(df) +
  geom_col(aes(x=Site, y=Geomean, fill=Year), position="dodge") +
  geom_point(aes(x=Site, y=Historical.Geomean),
             color="black", pch=18, show.legend = T) +
  theme_bw()

fw_ecoli_plot

Answer 1

这个怎么样：

Site <- c("A", "B", "C", "A", "B", "C")
Year <- c(2020, 2020, 2020, 2019, 2019, 2019)
Geomean <- c(65,184,27,21,67,51)
Historical.Geomean <- c(76,81,44,76,81,44)

df <- data.frame(Site, Year, Geomean, Historical.Geomean)

df$Year <- as.factor(df$Year)

fw_ecoli_plot <-
    ggplot(df) +
    geom_col(aes(x=Site, y=Geomean, fill=Year), position="dodge" ) +
    geom_point(aes(x=Site, y=Historical.Geomean, colour="Historical Mean"),
               pch=18) +
    scale_colour_manual(values="black") + 
    labs(colour="") + 
    theme_bw()

fw_ecoli_plot

Answer 2

通过将值放入aes，您基本上是在生成一个新的因子变量和一个图例。

如果您将值放在aes-> ggplot 之外，则不会创建图例。你可以试试：

  df %>% 
    ggplot(aes(x=Site, y=Geomean))+
    geom_col(aes(fill=Year), position="dodge") +
    geom_point(aes(x=Site, y=Historical.Geomean, color="black"), pch=18, show.legend = T) +
    scale_color_manual(values = c('black' = 'black'))+
    guides(fill = guide_legend(override.aes = list(shape = NA)))+
    theme_bw()