r - ggplot 形状与图例不匹配

Question

希望手动添加图例(在这种情况下，我不想让数据框变长)但图例形状与图表不匹配:

library(ggplot2)
mtcars$time <- 1:nrow(mtcars)
ggplot(mtcars) +
  
  #wt
  geom_line(aes(x = time, y = wt, color = "wt name"), size = 1.5) +
  geom_point(aes(x = time, y = wt, color = "wt name"), shape = 19, size = 4) +
  
  #drat
  geom_line(aes(x = time, y = drat   , color = "drat name"), size = 1.5) +
  geom_point(aes(x = time, y = drat   , color = "drat name"), shape = 8, size = 4) +
  
  scale_colour_manual(name = "legend", values = c("wt name"     = "#F8766D",  
                                                    "drat name"   = "#B79F00"))

结果:

其他问题建议使用 scale_shape_manual 但我无法让它工作:

ggplot(mtcars) +
  
  #wt
  geom_line(aes(x = time, y = wt, color = "wt name"), size = 1.5) +
  geom_point(aes(x = time, y = wt, color = "wt name"), size = 4) +
  
  #drat
  geom_line(aes(x = time, y = drat   , color = "drat name"), size = 1.5) +
  geom_point(aes(x = time, y = drat   , color = "drat name"), size = 4) +
  
  scale_colour_manual(name = "legend", values = c("wt name"     = "#F8766D",  
                                                    "drat name"   = "#B79F00")) +
  scale_shape_manual(values = c("wt name" = 19,
                                "drat name" = 8 ))

给出这个忽略形状:

有谁知道这个简单的问题需要改变什么吗？谢谢

Answer 1

如果您希望有一个自定义图例而不是 reshape 您的数据(这将是使用 ggplot 的标准方法)，您需要将形状映射为美学(即把 shape = 放在里面aes 调用，并给它你希望出现在图例上的名称)。如果您希望将它们合并到图例中，您还需要确保两个比例具有相同的 name = :

library(ggplot2)

mtcars$time <- 1:nrow(mtcars)

ggplot(mtcars, aes(x = time)) +
  geom_line(aes(y = wt, color = "wt name"), size = 1.5) +
  geom_point(aes(y = wt, color = "wt name", shape = "wt name"), size = 4) +
  geom_line(aes(y = drat, color = "drat name"), size = 1.5) +
  geom_point(aes(y = drat, color = "drat name", shape ="drat name"), size = 4) +
  scale_colour_manual(values = c("wt name" = "#F8766D", "drat name" = "#B79F00"),
                      name = "legend") +
  scale_shape_manual(values = c("wt name" = 19, "drat name" = 8 ), 
                     name = "legend")

或者如果你想将它们分开，给它们起不同的名字:

library(ggplot2)

mtcars$time <- 1:nrow(mtcars)

ggplot(mtcars, aes(x = time)) +
  geom_line(aes(y = wt, color = "wt name"), size = 1.5) +
  geom_point(aes(y = wt, color = "wt name", shape = "wt name"), size = 4) +
  geom_line(aes(y = drat, color = "drat name"), size = 1.5) +
  geom_point(aes(y = drat, color = "drat name", shape ="drat name"), size = 4) +
  scale_colour_manual(values = c("wt name" = "#F8766D", "drat name" = "#B79F00"),
                      name = "legend2") +
  scale_shape_manual(values = c("wt name" = 19, "drat name" = 8 ), 
                     name = "legend1")

并且，根据评论中的要求，如果您想要两个图例，但每个图例中只有一个颜色和形状，您将需要破解 breaks 和 guide ，因为这不是美学映射的标准用法。

library(ggplot2)
#> Warning: package 'ggplot2' was built under R version 3.6.3

mtcars$time <- 1:nrow(mtcars)

ggplot(mtcars, aes(x = time)) +
  geom_line(aes(y = wt, color = "wt name"), size = 1.5) +
  geom_point(aes(y = wt, color = "wt name", shape = "wt name"), size = 4) +
  geom_line(aes(y = drat, color = "drat name", size = "wt name")) +
  geom_point(aes(y = drat, color = "drat name", shape ="drat name"), size = 4) +
  scale_size_manual(values = c("wt name" = 1.5), breaks = "wt name", 
                    name = "legend2") +
  scale_colour_manual(values = c("wt name" = "#F8766D", "drat name" = "#B79F00"),
                      name = "legend1", breaks = "drat name") +
  scale_shape_manual(values = c("wt name" = 19, "drat name" = 8 ), 
                     name = "legend2", breaks = "wt name") +
  guides(colour = guide_legend(override.aes = list(shape = 8, color = "#B79F00")),
         shape = guide_legend(override.aes = list(shape = 19, color = "#F8766D")))

^{由 reprex package 于 2020-09-03 创建(v0.3.0)}