ggplot單值因子從圖例中刪除斜杠

Question

我想顯示一個簡單的geom_point ， geom_smooth和geom_abline以及有用的圖例。 不幸的是， geom_point和geom_smooth的簡單組合在點圖例上放置了一條水平線，而在所有圖例上添加geom_abline放置了對角斜線。

如何在圖例框僅包含“點”，“線”和“虛線”的地方創建簡單的視覺效果？

謝謝

例子：

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")

修復了geom_point圖例，但在其他圖例上保留了斜線

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")

我查看了以下問題，但不了解如何適用於我的情況：

• ggplot圖例斜線
• ggplot2圖例，用於abline和stat_smooth
• 包括手動添加的行到ggplot2指南圖例

Answer 1

對我來說，解決此問題的最簡單方法是根本不將所有內容都列為color 。 您可以使用size ， shape ， alpha等來分解圖例。

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

我的猜測： geom_point和geom_smooth都使用了color ，因此圖例嘗試將兩種geoms結合使用。 當您使用其他aes ，圖例會將它們作為單獨的屬性/層。

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 = "") 

希望能幫助到你！