Add single combined x-axis title to 2 patchwork plots-CodePudding

I have combined 2 separate ggplot2 plots using the patchwork package. How can I add a single combined x-axis title (e.g., "difference in SD units") to the patchwork plot below?

    dat_F <- structure(list(
  term = c("ExpA", "ExpA", "ExpB", "ExpB"), 
  estimate = c(-3.802316239, -5.885048428, -3.678601513, -4.103813546), 
  lci = c(-4.42722285, -6.476932582, -4.332540471, -4.751382827), 
  uci = c(-3.177409628, -5.293164273, -3.024662556, -3.456244265), 
  out = c("Out1", "Out2", "Out1", "Out2")), 
  class = "data.frame", row.names = c(NA, -4L))

    dat_M <- structure(list(
  term = c("ExpA", "ExpA", "ExpB", "ExpB"), 
  estimate = c(-1.134138758, -2.232236452, -0.935606149, -1.497766819), 
  lci = c(-1.841890314, -2.894980123, -1.662179615, -2.180915403), 
  uci = c(-0.426387201, -1.569492781, -0.209032682, -0.814618236), 
  out = c("Out3", "Out4", "Out3", "Out4")), 
  class = "data.frame", row.names = c(NA, -4L))

library(tidyverse)
library(patchwork)
library(RColorBrewer)

(plot_F <- ggplot(data = dat_F, aes(
  x = term, y = estimate, ymin = lci, ymax = uci))   
    theme_classic()   geom_pointrange(size = 0.3, aes(col = term))   coord_flip()  
    ggtitle("a. Females")   geom_hline(yintercept = 0, lty = 1, size = 0.1, col = "red")   
    facet_wrap(~ out, ncol = 1)   scale_color_brewer(palette = "Set2")  
    scale_y_continuous(limits = c(-7, 0.5), breaks=c(-6, -4, -2, 0))   
    ylab("")    theme(axis.title.y = element_blank(), axis.ticks.y = element_blank(), 
      strip.background = element_blank(), axis.text.y = element_blank(), 
      legend.title = element_blank(), legend.position  = "bottom")  
    guides(colour = guide_legend(override.aes = list(size=0.8)))) 

(plot_M <- ggplot(data = dat_M, aes(
  x = term, y = estimate, ymin = lci, ymax = uci))   
    theme_classic()   geom_pointrange(size = 0.3, aes(col = term))   coord_flip()  
    ggtitle("b. Males")   geom_hline(yintercept = 0, lty = 1, size = 0.1, col = "red")   
    facet_wrap(~ out, ncol = 1)   scale_color_brewer(palette = "Set2")  
    scale_y_continuous(limits = c(-7, 0.5), breaks=c(-6, -4, -2, 0))   
    ylab("")    theme(axis.title.y = element_blank(), axis.ticks.y = element_blank(), 
                      strip.background = element_blank(), axis.text.y = element_blank(), 
                      legend.title = element_blank(), legend.position  = "bottom")  
    guides(colour = guide_legend(override.aes = list(size=0.8)))) 

(combined_plot <- (plot_F   plot_M)   
  plot_layout(guides = "collect") & theme(
    legend.position = 'bottom', 
    legend.direction = "horizontal",
    text = element_text(size = 8)))

CodePudding user response：

TBMK patchwork has no option to "collect" the axis titles or to have only one title. But one option would be to add a combined axis title via a third plot:

library(tidyverse)
library(patchwork)
library(RColorBrewer)

plot_fun <- function(.data) {
  ggplot(data = .data, aes(
    x = estimate, y = term, xmin = lci, xmax = uci
  ))  
    theme_classic()  
    geom_pointrange(size = 0.3, aes(col = term))  
    ggtitle("a. Females")  
    geom_vline(xintercept = 0, lty = 1, size = 0.1, col = "red")  
    facet_wrap(~out, ncol = 1)  
    scale_color_brewer(palette = "Set2")  
    scale_x_continuous(limits = c(-7, 0.5), breaks = c(-6, -4, -2, 0))  
    ylab("")  
    theme(
      axis.title.y = element_blank(), axis.ticks.y = element_blank(),
      strip.background = element_blank(), axis.text.y = element_blank(),
      legend.title = element_blank(), legend.position = "bottom"
    )  
    guides(colour = guide_legend(override.aes = list(size = 0.8)))  
    labs(x = NULL)
}
plot_F <- plot_fun(dat_F)
plot_M <- plot_fun(dat_M)

axis_title <- ggplot(data.frame(x = c(0, 1)), aes(x = x))   geom_blank()  
  theme_void()   
  theme(axis.title.x = element_text())   
  labs(x = "difference in SD units")

(combined_plot <- ((plot_F   plot_M)  / axis_title)  
  plot_layout(guides = "collect", heights = c(40, 1)) & 
    theme(
      legend.position = "bottom",
      legend.direction = "horizontal",
      text = element_text(size = 8)
    )
)

CodePudding user response：

By adding textGrob after the patchwork call you can add text as wanted.

(combined_plot <- (plot_F   plot_M)   
    plot_layout(guides = "collect") & theme(
      legend.position = 'bottom', 
      legend.direction = "horizontal",
      text = element_text(size = 8)))


grid::grid.draw(grid::textGrob('diffence in SD units', x =.5, y=0.15))

CodePudding user response：

Rather than patchwork you could do this by combining the datasets then using a facet_grid. I had to add a new variable corresponding to the vertical facet location for each sex to do this but I think the result is nicer.

dat_F <- structure(list(
  term = c("ExpA", "ExpA", "ExpB", "ExpB"), 
  estimate = c(-3.802316239, -5.885048428, -3.678601513, -4.103813546), 
  lci = c(-4.42722285, -6.476932582, -4.332540471, -4.751382827), 
  uci = c(-3.177409628, -5.293164273, -3.024662556, -3.456244265), 
  out = c("Out1", "Out2", "Out1", "Out2"), 
  out2 = c("1", "2", "1", "2")), 
class = "data.frame", row.names = c(NA, -4L))

dat_M <- structure(list(
  term = c("ExpA", "ExpA", "ExpB", "ExpB"), 
  estimate = c(-1.134138758, -2.232236452, -0.935606149, -1.497766819), 
  lci = c(-1.841890314, -2.894980123, -1.662179615, -2.180915403), 
  uci = c(-0.426387201, -1.569492781, -0.209032682, -0.814618236), 
  out = c("Out3", "Out4", "Out3", "Out4"), 
  out2 = c("1", "2", "1", "2")), 
class = "data.frame", row.names = c(NA, -4L))


ggplot(rbindlist(list("Males"=dat_M,"Females"=dat_F), idcol="sex"), aes(
      x = term, y = estimate, ymin = lci, ymax = uci))   
     theme_classic()   
     geom_pointrange(size = 0.3, aes(col = term))   coord_flip()  
     geom_hline(yintercept = 0, lty = 1, size = 0.1, col = "red")   
     facet_grid(out2~sex)   scale_color_brewer(palette = "Set2")  
     scale_y_continuous(limits = c(-7, 0.5), breaks=c(-6, -4, -2, 0))   
     ylab("")    theme(axis.title.y = element_blank(), 
                       #axis.ticks.y = element_blank(),
                       strip.text.y = element_blank(),
                       strip.background = element_blank(), 
                       #axis.text.y = element_blank(), 
                       legend.title = element_blank(), 
                       legend.position  = "bottom")  
     guides(colour = guide_legend(override.aes = list(size=0.8)))  
     labs(y="Difference in SD units")
     geom_text(aes(label=out, y=-6, x=2.2))