Plot the convex hull in FDA plot - R - r

Question

I am trying to add a convex hull for each group in this plot using ggpubr package? Why it does not work?
Code:
library(dplyr)
library(MASS)
library(ggplot2)
library(scales)
library(ggpubr)
library(data.table)
irisfda <- fda(Species ~ ., data = iris, method = mars)
df1 <- cbind(data.frame(irisfda$fit$fitted.values), species = iris[,"Species"])
ggplot(df1) +
geom_point(aes(X1, X2, color = species, shape = species), size = 2.5) +
labs(x = "FDA1",y = "FDA1") +
stat_chull(aes(color = species, fill = species), geom = "polygon", alpha = 0.1)

Answer 1

You haven't told stat_chull where the x and y points are. You told geom_point where they were, but geoms and stats don't inherit from each other when you add them to a plot. You can either just add the x and y co-ordinates to stat_chull or, better yet, add them to the ggplot call. Then stat_chull can inherit them, and you can save on some typing.
Incidentally, you used library calls for dplyr, MASS, scales and data.table, which aren't needed for this example, but you forgot to put the library call for mda, which is needed:
library(ggplot2)
library(ggpubr)
library(mda)
irisfda <- fda(Species ~ ., data = iris, method = mars)
df1 <- cbind(data.frame(irisfda$fit$fitted.values), species = iris[,"Species"])
ggplot(df1, aes(x = X1, y = X2, color = species, shape = species)) +
geom_point(size = 2.5) +
labs(x = "FDA1",y = "FDA1") +
stat_chull(geom = "polygon", alpha = 0.1)