ggplot 将颜色回归线更改为渐变

Question

我用回归线制作了散点图：

ggplot(data = msleep, aes(x = bodywt, y = brainwt, color = bodywt)) +
  geom_point() +
  geom_smooth(method = 'lm', se = F, aes(color=..y..)) +
  labs(title = 'Scatter Plot of Body Weight vs. Brain Weight', x = 'Body Weight', y = 'Brain Weight')

但是，我想更改回归线的颜色，使其遵循与点相同的梯度（基于 bodywt），以便左下角为深蓝色，右上角为浅蓝色。我该怎么做？

Answer 1

一种选择是使用

ggforce::geom_link2

，但这需要手动创建回归线并将拟合值添加到数据集中：

library(ggplot2)
library(ggforce)

msleep$.fitted <- predict(
  lm(brainwt ~ bodywt, data = msleep), newdata = msleep
)

ggplot(data = msleep, aes(x = bodywt, y = brainwt, color = bodywt)) +
  geom_point() +
  geom_link2(
    aes(y = .fitted)
  ) +
  labs(
    title = "Scatter Plot of Body Weight vs. Brain Weight",
    x = "Body Weight",
    y = "Brain Weight"
  )
#> Warning: Removed 27 rows containing missing values (`geom_point()`).