Create a facet plot with different geom representations with same x-axis in R

Question

I would like to create a facet plot which share the same x-axis but have different y-axis and different geoms, for example, like this:

Here is a reproducible examples in which I generate two separate facet plots as per the above

library(ggplot2)

## create example data similar structure to my own
data(iris)
a <- iris
a$Species <- paste0(a$Species, "_a")
b <- iris
b$Species <- paste0(b$Species, "_b")
c <- iris
c$Species <- paste0(c$Species, "_c")
plot_data <- rbind(a, b, c)
plot_data$rep <- c(rep("a", nrow(iris)), rep("b", nrow(iris)), rep("c", nrow(iris)))

## facet boxplot
g1 <- ggplot() + geom_boxplot(data = plot_data, aes(Species, Sepal.Width, group = rep)) +
   theme(axis.text.x = element_text(angle = 90, vjust = 0.5, hjust=1)) +
   facet_wrap(rep~., scales = "free_x") + xlab("")

## facet heatmap
g2 <- ggplot() + geom_tile(data = plot_data, 
                           aes(factor(Species), rep, fill=Sepal.Width)) +
  scale_fill_continuous(low="white", high="#56B4E9", name="Sepal width") +
  facet_wrap(rep~., scales = "free_x") +
  theme(text=element_text(size=12),
        axis.text.x=element_text(angle=90, vjust=1, hjust=1),
        aspect.ratio=1)

## arrange
library(gridExtra)
grid.arrange(g1, g2, nrow = 2)

This produces this:

I would like the plots aligned and the legend offset to the right hand side as shown in the first image (put together using a dodgy cut and paste job). Ultimately this plots will be passed to a shiny app.

I have seen this post which may offer a solution but what I would really like to know is if the above is possible with facets alone or if there is a simpler solution.

Many thanks.

> sessionInfo()
R version 4.0.0 (2020-04-24)
Platform: x86_64-apple-darwin17.0 (64-bit)
Running under: macOS High Sierra 10.13.6

Matrix products: default
BLAS:   /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
LAPACK: /Library/Frameworks/R.framework/Versions/4.0/Resources/lib/libRlapack.dylib

locale:
[1] en_GB.UTF-8/en_GB.UTF-8/en_GB.UTF-8/C/en_GB.UTF-8/en_GB.UTF-8

attached base packages:
[1] stats4    parallel  stats     graphics  grDevices utils     datasets 
[8] methods   base     

other attached packages:
 [1] gridExtra_2.3        plotly_4.9.2.1       pRolocdata_1.26.0   
 [4] tidyr_1.1.0          reshape2_1.4.4       pRoloc_1.29.0       
 [7] BiocParallel_1.22.0  MLInterfaces_1.68.0  cluster_2.1.0       
[10] annotate_1.66.0      XML_3.99-0.3         AnnotationDbi_1.50.0
[13] IRanges_2.22.2       MSnbase_2.14.2       ProtGenerics_1.20.0 
[16] S4Vectors_0.26.1     mzR_2.22.0           Rcpp_1.0.4.6        
[19] Biobase_2.48.0       BiocGenerics_0.34.0  ggplot2_3.3.1       
[22] shinyhelper_0.3.2    colorspace_1.4-1     colourpicker_1.0    
[25] shinythemes_1.1.2    DT_0.13              shiny_1.4.0.2       
[28] dplyr_1.0.0

user_7941188 · Answer

The quickest fix is just putting the legend to the bottom. But here a solution with patchwork.

Note I add "global" theme options that apply to all plots to the call to patchwork, out of convenience and in order to reduce code. It makes it also much easier to change things when needed.

library(tidyverse)
library(patchwork)

ls_iris <- replicate(3, iris, simplify = FALSE)
names(ls_iris) <- letters[1:3]
plot_data <- 
  bind_rows(map2( ls_iris, letters[1:3], function(x, y) { 
  x[["Species"]] <- paste(x[["Species"]], y, sep ="_"); x}), .id = "rep")

## facet boxplot
g1 <- ggplot() + geom_boxplot(data = plot_data, aes(Species, Sepal.Width, group = rep)) +
  facet_wrap(rep~., scales = "free_x") +
  theme(axis.text.x = element_blank(), axis.title.x = element_blank()) # remove x labels and title

## facet heatmap
g2 <- ggplot() + geom_tile(data = plot_data, 
                           aes(factor(Species), rep, fill=Sepal.Width)) +
  scale_fill_continuous(low="white", high="#56B4E9", name="Sepal width") +
  facet_wrap(rep~., scales = "free_x") +
  theme(axis.text.x=element_text(angle=90, vjust=1, hjust=1), 
        strip.background = element_blank(),
        strip.text = element_blank()) # remove facet strips
g1/g2 & 
  theme(legend.position = "bottom") # theme elements that are for both plots are more conveniently passed to the patchwork call.

^{Created on 2020-07-09 by the reprex package (v0.3.0)}

Create a facet plot with different geom representations with same x-axis in R

1 Answers