Making a circular barplot with a hollow center (aka race track plot)

Question

I was asked to recreate the following style of plot. (Please ignore the question of whether this is a good type of visualization and charitably consider this as adding a colorf

Answer 1

Since the plot is circular, it can be easily done by circlize package.

First the data:

Category <- c("Electronics", "Appliances", "Books", "Music", "Clothing", 
        "Cars", "Food/Beverages", "Personal Hygiene", 
        "Personal Health/OTC", "Hair Care")
Percent <- c(81, 77, 70, 69, 69, 68, 62, 62, 61, 60)
color = rainbow(length(Percent))

Reverse the three vectors since circlize adds each element from inside to outside by default:

Category = rev(Category)
Percent = rev(Percent)
color = rev(color)

If you image the circle is a bent plot region, then it is just adding rectangles, lines and texts.

library(circlize)

par(mar = c(1, 1, 1, 1))
circos.par("start.degree" = 90)
circos.initialize("a", xlim = c(0, 100)) # 'a` just means there is one sector
circos.trackPlotRegion(ylim = c(0.5, length(Percent)+0.5), track.height = 0.8, 
    bg.border = NA, panel.fun = function(x, y) {
    xlim = get.cell.meta.data("xlim") # in fact, it is c(0, 100)
    for(i in seq_along(Percent)) {
        circos.lines(xlim, c(i, i), col = "#CCCCCC")
        circos.rect(0, i - 0.45, Percent[i], i + 0.45, col = color[i], 
            border = "white")
        circos.text(xlim[2], i, paste0(Category[i], " - ", Percent[i], "%"), 
            adj = c(1, 0.5)) 
    }
})
circos.clear()

text(0, 0, "GLOBAL", col = "#CCCCCC")

Answer 2

Here's a non-ggplot2 (base R graphics) solution using the plotrix package, which contains two nice functions: draw.circle() and draw.arc():

circBarPlot <- function(x, labels, colors=rainbow(length(x)), cex.lab=1) {
  require(plotrix)
  plot(0,xlim=c(-1.1,1.1),ylim=c(-1.1,1.1),type="n",axes=F, xlab=NA, ylab=NA)
  radii <- seq(1, 0.3, length.out=length(x))
  draw.circle(0,0,radii,border="lightgrey")
  angles <- (1/4 - x)*2*pi
  draw.arc(0, 0, radii, angles, pi/2, col=colors, lwd=130/length(x), lend=2, n=100)
  ymult <- (par("usr")[4]-par("usr")[3])/(par("usr")[2]-par("usr")[1])*par("pin")[1]/par("pin")[2]
  text(x=-0.02, y=radii*ymult, labels=paste(labels," - ", x*100, "%", sep=""), pos=2, cex=cex.lab)
}

circBarPlot(Percent/100, Category)
text(0,0,"GLOBAL",cex=1.5,col="grey")

It gives me:

Answer 3

Another base solution that doesn't rely on plotrix package:

circular.barplot<-function(values, labels, col, cex){
    df<-data.frame(values=sort(values), labels=labels[order(values)])
    col<-col[order(values)]
    plot(NA,xlim=c(-1.3,1.3),ylim=c(-1.3,1.3),axes=F, xlab=NA, ylab=NA, asp=1)
    t<-sapply(df$values,function(x).5*pi-seq(0, 2*pi*x/100,length=1000))
    x<-sapply(1:nrow(df),function(x)(.3+x/nrow(df))*cos(t[,x]))
    y<-sapply(1:nrow(df),function(x)(.3+x/nrow(df))*sin(t[,x]))
    for(i in 1:nrow(df)){
        lines(x=x[,i],y=y[,i],col=col[i],lwd=10,lend=1)
        text(x[1,i],y[1,i],paste(df$labels[i]," - ",df$values[i],"%",sep=""),
             pos=2,cex=cex)
        }
    }

Answer 4

I think an immediate fix is to create some "empty" entries. I'd create internetImportance data.frame like this:

Category <- c("Electronics", "Appliances", "Books", "Music", "Clothing", 
        "Cars", "Food/Beverages", "Personal Hygiene", 
        "Personal Health/OTC", "Hair Care")
Percent <- c(81, 77, 70, 69, 69, 68, 62, 62, 61, 60)

internetImportance <- data.frame(Category,Percent)

len <- 4
df2 <- data.frame(Category = letters[1:len], Percent = rep(0, len), 
                                 Category2 = rep("", len))
internetImportance$Category2 <- 
 paste0(internetImportance$Category," - ",internetImportance$Percent,"%")

# append number to category name
internetImportance <- rbind(internetImportance, df2)

# set factor so it will plot in descending order 
internetImportance$Category <-
    factor(internetImportance$Category, 
    levels=rev(internetImportance$Category))

And then I'd plot ggplot2 with fill=category2 as follows:

ggplot(internetImportance, aes(x = Category, y = Percent,
    fill = Category2)) + 
    geom_bar(width = 0.9, stat="identity") + 
    coord_polar(theta = "y") +
    xlab("") + ylab("") +
    ylim(c(0,100)) +
    ggtitle("Top Product Categories Influenced by Internet") +
    geom_text(data = internetImportance, hjust = 1, size = 3,
              aes(x = Category, y = 0, label = Category2)) +
    theme_minimal() +
    theme(legend.position = "none",
          panel.grid.major = element_blank(),
          panel.grid.minor = element_blank(),
          axis.line = element_blank(),
          axis.text.y = element_blank(),
          axis.text.x = element_blank(),
          axis.ticks = element_blank())

This gives me:

You can add a geom_text(label="GLOBAL", x=.5, y=.5, size=4) + before theme_minimal to add the text GLOBAL.