Vinay vinay Vinay vinay - 22 days ago 8
R Question

Positioning values of stacked barchart in the center using ggplot2

I've created a stacked barchart and faceted using two variables. I'm unable to position the values in the barchart in the middle, it either appears at the extremes or overlaps. The expected image is the following:

link to the image

I've pasted the script below. Any help would be appreciated.

library(dplyr)

library(reshape2)

library(ggplot2)


year<-c("2000","2000","2010","2010","2000","2000","2010","2010")

area<-c("Rural","Rural","Rural","Rural","Urban","Urban","Urban","Urban")

sex<-c("Male","Female","Male","Female","Male","Female","Male","Female")

city<-c(58,61,74,65,51,55,81,54)`

village<-c(29,30,20,18,42,40,14,29)

town<-c(13,9,6,17,7,5,5,17)

data<-cbind.data.frame(year,area,sex,city,village,town)

dre<-melt(data,id.vars = c("year","area","sex"))

dre <- arrange(dre,year,area,sex,variable) %>%
mutate(pos = cumsum(value) - (0.5 * value))


a <- ggplot(dre,aes(factor(sex),value,fill=variable)) +
geom_bar(stat='identity',position="stack")

b <- a +
facet_wrap(factor(year)~area)

c <- b +
geom_text(aes(label=paste0(value,"%"),y=pos),
position="stack",size=2,hjust=0.85,color="black")

d <- c +
coord_flip() +
theme_bw() +
scale_fill_brewer()

print(d)

Answer

You no longer need to calculate the position variable. Starting in ggplot2_2.2.0, text can be stacked and centered via position_stack.

The relevant line of geom_text code is below. Notice I don't need to use the "pos" variable at all for text placement.

geom_text(aes(label=paste0(value,"%")),
              position = position_stack(vjust = .5), size = 2, color = "black")

The code for the plot and the resulting graph:

ggplot(dre, aes(factor(sex), value, fill = variable)) + 
    geom_col() +
    facet_wrap(factor(year)~area) +
    geom_text(aes(label = paste0(value,"%")),
              position = position_stack(vjust = .5), size = 2, color = "black") +
    coord_flip() +
    theme_bw() +
    scale_fill_brewer() 

enter image description here