How to fix the warning in ggplot2: Ignoring unknown aesthetics: label-CodePudding

I am trying to make a PCA score plot using ggplot2, then convert the ggplot object into interactive plotly. The interactive plot will show the sample name if the cursor will hover on a point.

Below is my minimum example, and it works quite well. but I got the following warning:

In ggplot2::geom_point(data = df_pcs, mapping = aes(x = PC1, y = PC2, : Ignoring unknown aesthetics: label

I tried to use text aesthetics, but then the sample names are now shown in the interactive plot.

How can I fix this warning?

Thanks.

library(dplyr)
library(ggplot2)
library(poorly)
#(1) example data
dat <-  iris[1:4]
Group <- iris$Species

#(2) perform PCA
df_pca <- prcomp(dat, center = TRUE, scale. = TRUE)
df_pcs <- data.frame(df_pca$x, Group = Group)


#(3) plot
hull_group <- df_pcs %>%
  dplyr::mutate(Sample_Name = rownames(df_pcs)) %>%
  dplyr::group_by(Group) %>%
  dplyr::slice(chull(PC1, PC2))

p2 <- ggplot2::ggplot()  
  ggplot2::geom_polygon(data = hull_group, 
                        mapping = aes(x = PC1, y = PC2, fill = Group, group = Group), 
                        alpha = 0.2)  
  ggplot2::geom_point(data = df_pcs, 
                      mapping = aes(x = PC1, y = PC2, color = Group, label = rownames(df_pcs)), 
                      size = 3)  
  ggplot2::theme_bw()

plotly::ggplotly(p2, tooltip = "label")

CodePudding user response：

This works for me:

library(dplyr)
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union
library(ggplot2)
#library(poorly)
#(1) example data
dat <-  iris[1:4]
Group <- iris$Species

#(2) perform PCA
df_pca <- prcomp(dat, center = TRUE, scale. = TRUE)
df_pcs <- data.frame(df_pca$x, Group = Group)


#(3) plot
hull_group <- df_pcs %>%
  dplyr::mutate(Sample_Name = rownames(df_pcs)) %>%
  dplyr::group_by(Group) %>%
  dplyr::slice(chull(PC1, PC2))

p2 <- ggplot2::ggplot(df_pcs, aes(text = rownames(df_pcs)))  
  ggplot2::geom_polygon(data = hull_group, 
                        mapping = aes(x = PC1, y = PC2, fill = Group, group = Group), 
                        alpha = 0.2, inherit.aes = FALSE)  
  ggplot2::geom_point(mapping = aes(x = PC1, y = PC2, color = Group), 
                      size = 3)  
  ggplot2::theme_bw()

plotly::ggplotly(p2, tooltip = "text")

^{Created on 2023-01-08 by the reprex package (v2.0.1)}

I think the problem was that text and label are not known aesthetics for the point geometry. If you put the text aesthetic in the call to ggplot(), then the warning goes away.