将等量曲线添加到g图中的散点图中

Question

我很好奇，是否有人知道如何创建一个带有isoquant曲线的热图，该曲线识别所有的x和y组合，其乘积等于某个常数。最后的产品应该如下所示：

等距曲线散射图

下面是生成我的绘图所用的代码，但是现在我无法像上面的图片所描述的那样在图中得到曲线：

vs.vpd.by.drop_days <- ggplot(event_drops, aes(vs, vpd)) +
  geom_point(aes(color = day_since), size = 2, alpha = 0.2) +
  scale_color_gradientn(colors = c("darkblue","green","yellow","red"),
                        breaks = c(0,25,50,75),
                        limits = c(0,75),
                        name = "Days since \n first drop") +
  ggtitle("Drops by VPD and Wind Speed") +
  theme(plot.title = element_text(size = 18, face = "bold", hjust = 0.5),
        axis.title = element_text(size = 15)) +
  xlab(label = "Wind Speed (mph)") +
  ylab(label = "Vapor Pressure Deficit") +
  expand_limits(x = 0, y = 0) +
  scale_x_continuous(expand = c(0, 0), limits = c(0,20)) + 
  scale_y_continuous(expand = c(0, 0), limits = c(0,5)) 

vs.vpd.by.drop_days

Answer 1

实现这一目标的一个选择是geom_function。

使用mtcars作为示例数据：

library(ggplot2)

ggplot(mtcars, aes(hp, mpg, color = disp)) +
  geom_point() +
  geom_function(fun = function(x) 3000 / x)

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