Is there a way to label each cluster generated by lda() - r

Question

using lda() and ggplot2 I can make a canonical plot with confidence ellipses. Is there a way to add labels for each group on the plot (labeling each cluster with a group from figure legend)?
# for the universality lda(Species~., data=iris) would be analogous
m.lda <- lda(Diet ~ ., data = b)
m.sub <- b %>% dplyr::select(-Diet) %>% as.matrix
CVA.scores <- m.sub %*% m.lda$scaling
m.CV <- data.frame(CVA.scores)
m.CV$Diet <- b$Diet
m.cva.plot <-
ggplot(m.CV, aes(x = LD1, y = LD2)) +
geom_point(aes(color=Diet), alpha=0.5) +
labs(x = "CV1", y = "CV2") +
coord_fixed(ratio=1)
chi2 = qchisq(0.05,2, lower.tail=FALSE)
CIregions.mean.and.pop <-
m.CV %>%
group_by(Diet) %>%
summarize(CV1.mean = mean(LD1),
CV2.mean = mean(LD2),
mean.radii = sqrt(chi2/n()),
popn.radii = sqrt(chi2))
m.cva.plot2 <-
m.cva.plot +
geom_circle(data = CIregions.mean.and.pop,
mapping = aes(x0 = CV1.mean, y0 = CV2.mean, r = mean.radii),
inherit.aes = FALSE) +
geom_circle(data = CIregions.mean.and.pop,
mapping = aes(x0 = CV1.mean, y0 = CV2.mean, r = popn.radii),
linetype = "dashed",
inherit.aes = FALSE)

Answer 1

The labels can be placed with either geom_text or geom_label. In the case below I will use geom_label, with the y coordinate adjusted by adding popn.radii the radii of the outer circles.
The code in the question is adapted to use built-in data set iris, like the question itself says.
m.cva.plot2 +
geom_label(data = CIregions.mean.and.pop,
mapping = aes(x = CV1.mean,
y = CV2.mean + popn.radii,
label = Species),
label.padding = unit(0.20, "lines"),
label.size = 0)
Reproducible code
library(dplyr)
library(ggplot2)
library(ggforce)
library(MASS)
b <- iris
m.lda <- lda(Species~., data=iris) #would be analogous
#m.lda <- lda(Diet ~ ., data = b)
m.sub <- b %>% dplyr::select(-Species) %>% as.matrix
CVA.scores <- m.sub %*% m.lda$scaling
m.CV <- data.frame(CVA.scores)
m.CV$Species <- b$Species
m.cva.plot <-
ggplot(m.CV, aes(x = LD1, y = LD2)) +
geom_point(aes(color=Species), alpha=0.5) +
labs(x = "CV1", y = "CV2") +
coord_fixed(ratio=1)
chi2 = qchisq(0.05,2, lower.tail=FALSE)
CIregions.mean.and.pop <-
m.CV %>%
group_by(Species) %>%
summarize(CV1.mean = mean(LD1),
CV2.mean = mean(LD2),
mean.radii = sqrt(chi2/n()),
popn.radii = sqrt(chi2))
m.cva.plot2 <-
m.cva.plot +
geom_circle(data = CIregions.mean.and.pop,
mapping = aes(x0 = CV1.mean, y0 = CV2.mean, r = mean.radii),
inherit.aes = FALSE) +
geom_circle(data = CIregions.mean.and.pop,
mapping = aes(x0 = CV1.mean, y0 = CV2.mean, r = popn.radii),
linetype = "dashed",
inherit.aes = FALSE)