ggplot单值因子从图例中删除斜杠

Question

我想显示一个简单的geom_point，geom_smooth和geom_abline并附上有用的图例。不幸的是，geom_point和geom_smooth的简单组合在点图例上放置了一条水平线，在所有图例上添加了geom_abline处了斜线。

如何创建简单的视觉效果，其中图例框仅包含“点”，“线”和“虚线”？

谢谢

示例：

Geom_point和geom_smooth

mtcars %>%
  ggplot() +
  geom_point(aes(x = carb, y = mpg, color = "Points")) +
  geom_smooth(aes(x = carb, y = mpg, color = "Trendline")) +
  theme(legend.position="bottom") +
  labs(x = "carb",
    y = "mpg",
    color = "LEGEND")

Geom_point，geom_smooth和geom_abline

mtcars %>%
  ggplot() +
  geom_point(aes(x = carb, y = mpg, color = "Points")) +
  geom_smooth(aes(x = carb, y = mpg, color = "Trendline")) +
  geom_abline(aes(slope = 1, intercept = 10, color = "ZCustom"), linetype = "dashed") +
  theme(legend.position="bottom") +
  labs(x = "carb",
    y = "mpg",
    color = "LEGEND")

修复了geom_point图例，但在其他图例上保留了斜线

mtcars %>%
  ggplot() +
  geom_point(aes(x = carb, y = mpg, color = "Points")) +
  geom_smooth(aes(x = carb, y = mpg, color = "Trendline")) +
  geom_abline(aes(slope = 1, intercept = 10, color = "ZCustom"), linetype = "dashed") +
  scale_color_manual(values = c("red", "blue", "black"),
                 label = c("Points", "Trendline", "Custom"),
                 guide = guide_legend(override.aes = list(
                   linetype = c("blank", "solid", "dashed"),
                   shape = c(16, NA, NA)))) +
  theme(legend.position="bottom") +
  labs(x = "carb",
    y = "mpg",
    color = "LEGEND")

我看过以下问题，但不了解如何适用于我的情况：

• ggplot legend slashes
• ggplot2 legend for abline and stat_smooth
• Include manually-added lines to ggplot2 guide legend

Answer 1

对我来说，解决此问题的最简单方法是根本不将所有内容都列为color。您可以使用size，shape，alpha等来分解图例。

mtcars %>%
  ggplot() +
  geom_point(aes(x = carb, y = mpg, shape = "")) +
  geom_smooth(aes(x = carb, y = mpg, alpha = "")) +
  geom_abline(aes(slope = 1, intercept = 10, color = ""), linetype = "dashed") +
  theme(legend.position="bottom") +
  labs(x = "carb",
    y = "mpg",
    shape = "Points",
    alpha = "Trendline",
    color = "ZCustom")

Answer 2

我的猜测：color和geom_point都使用geom_smooth，因此图例尝试将两个几何合并。 当您使用其他aes时，图例会将它们作为单独的属性/层。

mtcars %>%
  ggplot( aes(x = carb, y = mpg) ) + 
  geom_point( aes(fill = "Points") ) +    # use 'fill' rather than 'color'
  geom_smooth( aes(color = "Trendline")  ) +
  theme(legend.position = "bottom") +
  labs(x = "carb", y = "mpg", color = "", fill = "") 

希望有帮助！