正确显示ggplot图例以进行线条/形状组合

Question

我正在尝试使用三个不同的彩色线为三个组创建一个绘图，但是只有两个组具有点标记。我可以使图正确显示，但图例在所有三个组中都显示相同的点标记。

我使用mpg数据集创建了一个可复制的示例

shouldComponentUpdate

“ 4”组在图例中不应有点标记，而“ r”组应显示三角形标记

预先感谢您的帮助

Answer 1

在您的linetype中将geom_line()自变量与目标变量（在这种情况下为drv）相加，即可得到预期的结果。

library(tidyverse)

ggplot(mpg) +
  geom_line(mapping = aes(x = displ, y = cty, color = drv, linetype = drv), size = 1) +
  geom_point(data = subset(mpg, drv != '4'), mapping = aes(x = displ, y = cty, color = drv, shape = drv), size = 3) +
  scale_color_manual(name="Variable", labels = c("4", "f", "r"), values=c("4" = "#DA2128", "f" = "black", "r" = "blue"))  +
  scale_shape_manual(name="Variable", labels = c("f", "r"), values = c("f" = 16, "r" = 17), guide = FALSE)

Answer 2

尝试一些字母

ggplot(mpg, aes(x = displ, y = cty, color = drv, shape = drv)) +
  geom_line() +
  geom_point(aes(alpha=drv), size = 3) + 
  scale_alpha_manual(values = c(0,1,1)) +
  scale_shape_manual(values = c(1,16, 17))

或者简单地将形状4设置为NA

ggplot(mpg, aes(x = displ, y = cty, color = drv, shape = drv)) +
  geom_line() +
  geom_point(size = 3) + 
  scale_shape_manual(values = c(NA, 16, 17)) +
  scale_color_manual(values = c("#DA2128", "black", "blue"))

Answer 3

您还可以为shape禁用图例，并在shape图例中手动设置color的值： ggplot(mpg) + geom_line(mapping = aes(x = displ, y = cty, color = drv), size = 1) + geom_point(data = subset(mpg, drv != '4'), mapping = aes(x = displ, y = cty, color = drv, shape = drv), size = 3) + scale_color_manual(name="Variable", labels = c("4", "f", "r"), values=c("4" = "#DA2128", "f" = "black", "r" = "blue"), guide=guide_legend(override.aes = list(shape = c("4" = NA, "f" = 16, "r" = 17)))) + scale_shape_manual(values = c("f" = 16, "r" = 17), guide=F)