(R) 如何在 ggplot2 中根据颜色、线型和点形状获取图例？

Posted 2023-02-16

【中文标题】(R) 如何在 ggplot2 中根据颜色、线型和点形状获取图例？

【英文标题】：(R) How to get a legend in ggplot2 based on color, linetype and point shape?

【发布时间】：2021-09-05 12:55:10

【问题描述】：

如何根据点的颜色、线型和形状来区分 y1 和 y2，以获取以下数据的图例？ （sd 只是表示标准差）

x <- c(2.5, 1.25, 0.625, 0.3125, 0.15625, 0.078, 0.039, 0)

y2<- c(1.422616667,
           1.26845,
           1.149133333,
           0.842166667,
           0.4697,
           0.251566667,
           0.118133333,
           0.000233333)

y1<- c(1.4364,
          1.342333333,
          1.155216667,
          0.88485,
          0.502266667,
          0.2673,
          0.110783333,
          -0.000233333)

sd1<- c(0.12252713,
        0.09232539,
        0.046399526,
        0.078883881,
        0.014853518,
        0.039726687,
        0.012708213,
        0.005837722)

sd2<- c(0.183093342,
        0.122781068,
        0.088565849,
        0.110920994,
        0.036569081,
        0.02125754,
        0.012588791,
        0.002873616)

这是我尝试过的：

data = data.frame(y1, y2, sd1, sd2, Conc, colors)
colors<- c("y1" = "red", "y2" = "blue")
ggplot(data = data, aes(x = Conc, y = y1))+
  geom_point(aes(x = Conc, y = y1), shape = 15, size = 3)+
  geom_line(aes(x = Conc, y = y1, color = "y1"), linetype = "solid", size = 1.3)+
  geom_line(aes(x = Conc, y = y2, color = "y2"), linetype = "dashed", size = 1.3)+
  geom_point(aes(x = Conc, y = y2), shape = 2, size = 3)+
  geom_errorbar(aes(ymin =y1 - sd1, ymax = y1 + sd1), color = "red")+
  geom_errorbar(aes(ymin = y2 - sd2, ymax = y2 + sd2), color = "blue")+
  labs(x = "Concentration in micg per mL", 
       y = "Absorbance",
       colors = "Legend",
       title = "Absorbance as a function of Concentration")+
  scale_color_manual(values = colors)+
  theme(plot.title = element_text(hjust = 0.5))+
  theme(plot.title = element_text(face = "bold"))

我可以根据线条颜色获得图例，但也不能获得线型和点形状。有什么想法吗？

【问题讨论】：

这能回答你的问题吗？ Add legend to ggplot2 line plot

您的示例不可重现：您的数据包含 Conc 和颜色列，而您没有提供该列的值

【参考方案1】：

当然，您也可以提供线型和形状的图例。最简单的方法是首先将数据重塑为长格式，例如通过将y1 和y2 的数据放入单独的数据帧中，添加一个 id 变量并将这些数据帧绑定到一个。这样做您将id 变量映射到color、linetype 和shape 上，并且您只需要一个geom_point、一个geom_line...来创建您的绘图。线型和shape 的值可以通过scale_linetype/shape_manual 设置，就像您已经为颜色所做的那样。最后，要将所有图例合并为一组，为 labs 中的每个图例设置相同的标签，或者如果您更喜欢单独的图例，只需使用不同的标签：

library(ggplot2)

data = list(data.frame(y = y1, sd = sd1, Conc = x, id = "y1"), data.frame(y = y2, sd = sd2, Conc = x, id = "y2"))
data <- do.call("rbind", data)

colors<- c("y1" = "red", "y2" = "blue")
ltys <- c("y1" = "solid", "y2" = "dashed")
shapes <- c("y1" = 15, "y2" = 2)

ggplot(data = data, aes(x = Conc, y = y))+
  geom_point(aes(shape = id), size = 3) +
  geom_line(aes(color = id, linetype = id), size = 1.3) +
  geom_errorbar(aes(ymin = y - sd, ymax = y + sd, color = id)) +
  scale_color_manual(values = colors) +
  scale_linetype_manual(values = ltys) +
  scale_shape_manual(values = shapes) +
  labs(x = "Concentration in micg per mL", 
       y = "Absorbance",
       color = "Legend", shape = "Legend", linetype = "Legend",
       title = "Absorbance as a function of Concentration")+
  #scale_color_manual(values = colors)+
  theme(plot.title = element_text(hjust = 0.5))+
  theme(plot.title = element_text(face = "bold"))

^{由reprex package (v2.0.0) 于 2021-06-22 创建}