How to plot two grouped barplots (vertically) with single x axis in R?

Question

I have four dataframes and i plot dataframe 1 and dataframe two in a grouped barplot and dataframe3 and dataframe 4 in a grouped bar plot. So I have 2 grouped bar plots through this codes. All values are kept same just to serve as an example:

library(tidyverse)

dataframe2 = read.table(text="sl zone   meangpp
                        1     1 5.4153407
                        2     2 4.2429236
                        3     3 4.5719178
                        4     4 3.1215946
                        5     5 4.9222054
                        6     6 3.0384872
                        7     7 1.9293729
                        8     8 8.9709741
                        9     9 7.8904906
                        10   10 6.6410986
                        11   12 5.5011823", header=T)

dataframe1 = read.table(text="sl zone   meangpp
                        1     1 4.050161
                        2     2 7.729265
                        3     3 3.408220
                        4     4 4.884040
                        5     5 4.258422
                        6     6 2.906374
                        7     7 2.241984
                        8     8 4.703197
                        9     9 3.617657
                        10   10 2.712997
                        11   12 3.589406", header=T)

df <- bind_rows("dataframe1" = dataframe1, "dataframe2" = dataframe2, .id = "groups")

df %>% 
  ggplot(aes(x=factor(zone), y=meangpp, fill = groups)) + 
  geom_col(position = position_dodge())









#PLOTTING NPP


library(tidyverse)

dataframe3 = read.table(text="sl zone   meannpp
                        1     1 5.4153407
                        2     2 4.2429236
                        3     3 4.5719178
                        4     4 3.1215946
                        5     5 4.9222054
                        6     6 3.0384872
                        7     7 1.9293729
                        8     8 8.9709741
                        9     9 7.8904906
                        10   10 6.6410986
                        11   12 5.5011823", header=T)

dataframe4 = read.table(text="sl zone   meannpp
                        1     1 4.050161
                        2     2 7.729265
                        3     3 3.408220
                        4     4 4.884040
                        5     5 4.258422
                        6     6 2.906374
                        7     7 2.241984
                        8     8 4.703197
                        9     9 3.617657
                        10   10 2.712997
                        11   12 3.589406", header=T)

df <- bind_rows("dataframe3" = dataframe3, "dataframe4" = dataframe4, .id = "groups")

df %>% 
  ggplot(aes(x=factor(zone), y=meannpp, fill = groups)) + 
  geom_col(position = position_dodge())

Now through the code above I get 2 separate barplots. I am trying to arrange them like:

I need the 2 panels to be blended together and the bounding boxes touch and give axis only once and color key also given once. However the factors in x axis should be labelled categorially in classes of "A","B" "C" and so on. How can this be achieved in R?

user_12993861 · Answer

This could be achieved via e.g. patchwork:

For the axis labels you could make a named vector of labels which you can then pass to the axis via scale_x_discrete(labels = ...)
Remove the axis from your first plot.
I also removed the plot.margins from the single plots
Glue the plots together using patchwork
To make sure that the legends get merged make use of plot_layout(guides = 'collect') and make sure that the legends are identical (!!), i.e. identical names, labels, .... For this reason I removed the data frame labels and simply called them 1 and 2 for both plots and set the labels via scale_fill_discrete

library(patchwork)

df <- bind_rows(dataframe1, dataframe2, .id = "id")

axis_labels <- c("first", "second", "third", "D", "E", "F", "G", "H", "I", "J", "K", "L")
axis_labels <- setNames(axis_labels, 1:12)

p1 <- ggplot(df, aes(x=factor(zone), y=meangpp, fill = id)) + 
  geom_col(position = position_dodge()) +
  scale_fill_discrete(labels = c("1" = "dataframe 1 & 3", "2" = "dataframe 2 & 4")) +
  scale_x_discrete(labels = axis_labels) +
  theme(axis.title.x = element_blank(), 
        axis.line.x = element_blank(), 
        axis.text.x = element_blank(),
        axis.ticks.x = element_blank()) +
  theme(plot.margin = unit(rep(0, 4), "pt"))  

df <- bind_rows(dataframe3, dataframe4, .id = "id")

p2 <- ggplot(df, aes(x=factor(zone), y=meannpp, fill = id)) + 
  geom_col(position = position_dodge()) +
  scale_fill_discrete(labels = c("1" = "dataframe 1 & 3", "2" = "dataframe 2 & 4")) +
  scale_x_discrete(labels = axis_labels) +
  theme(plot.margin = unit(rep(0, 4), "pt"))

p1 / p2 +
  plot_layout(guides = 'collect')

How to plot two grouped barplots (vertically) with single x axis in R?

1 Answers