如何使用ggplot在同一个绘图中绘制两个平滑样条曲线？

Question

例如，我有几个这样的情节：

ggplot(mpg, aes(displ, hwy)) +
geom_point() +
geom_smooth(method = "lm", formula = y ~ splines::bs(x, 3), se = T)

是否有可能将这些中的2个绘制在同一个图中？

Answer 1

如果您只想添加其他功能，请添加另一个图层：+ geom_smooth()

ggplot(mpg, aes(displ, hwy)) + geom_point() + 
geom_smooth(method = "lm", formula = y ~ splines::bs(x, 3), se = T) +
geom_smooth(method = "lm", formula = y ~ splines::bs(x, 4), se = T)

如果您想要添加其他数据框中的数据，请在df中添加geom_smooth个信息：

ggplot(mpg, aes(displ, hwy)) + geom_point() + 
geom_smooth(method = "lm", formula = y ~ splines::bs(x, 3), se = T) + 
geom_smooth(data = mpg, aes(x = displ, y = cyl), method = "lm", formula = y ~ splines::bs(x, 4), se = T)

最后，自定义颜色和图例： color参数必须位于aes内以显示在图例

中

ggplot(mpg, aes(displ, hwy)) + geom_point() + 
geom_smooth(aes(color = "B"),method = "lm", formula = y ~ splines::bs(x, 3), se = T) + 
geom_smooth(data = mpg, aes(x = displ, y = cyl, color = "A"), method = "lm", formula = y ~ splines::bs(x, 4), se = T) + 
scale_color_manual("Legend Title", values = c("A" = "red", "B" = "blue"))