在ggplot object、R中调整图例标题position

Question

In the following example I am using factoextra and FactoMineR to create a biplot. The plot has a colour bar and the title is technically centered in the middle, but it is in the middle of the colour bar and the tick numbers inclusive, making it look too low, particularly when I have another legend next to it.

library("factoextra")
library("FactoMineR")

data("decathlon2")
df <- decathlon2[1:23, 1:10]

res.pca <- PCA(df,  graph = FALSE)

p<-fviz_pca_var(res.pca, col.var="contrib", 
             gradient.cols = c("#00AFBB", "#E7B800", "#FC4E07"),
             repel = TRUE)+
  theme(legend.position='bottom')

p$labels$colour<-'Contribution to variance'

I would like to raise it, and I have tried using +guides(colour=guide_legend(title.vjust = 0.5))

p<-fviz_pca_var(res.pca, col.var="contrib", 
             gradient.cols = c("#00AFBB", "#E7B800", "#FC4E07"),
             repel = TRUE)+
  theme(legend.position='bottom')+
  guides(colour=guide_legend(title.vjust = 0.5))

p$labels$colour<-'Contribution to variance'

But this gets rid of the colour bar in exchange for letters. Can anyone help solve this? FYI the plot is a ggplot object. Thank you

Answer 1

You need to use guide_colourbar() rather than guide_legend() when trying to modify it:

p <- fviz_pca_var(res.pca, col.var = "contrib", 
                gradient.cols = c("#00AFBB", "#E7B800", "#FC4E07"),
                repel = TRUE)+
    # You can use labs() to set labels
    labs(colour = "Contribution to variance") +
    guides(colour = guide_colourbar(title.vjust = 0.9)) +
    theme(legend.position = 'bottom')
print(p)

Answer 2

You can use the legend.title parameter inside theme() to change adjust the position of the legend title:

theme(legend.position = "bottom",
      legend.title = element_text(vjust = 0.75)
      )