This page aims to describe how to build a basic
circle packing chart with only one
level of hierarchy. It uses the
packcircle package for
circle position, and
ggplot2 for drawing.
This page aims to describe how to build a basic circle packing chart with only one level of hierarchy. Basically, you just represent each entity or individual of your dataset with a circle, its size depending on a provided value.
It is like a barplot, but you use circle size instead of bar length. It is close to a bubble plot, but X and Y positions do not mean anything. It is a circle version of a treemap.
Calculating the arrangement of dots is not a trivial problem. The
packcircles library solves it and output coordinates of
every points of the circle edges.
Finally, ggplot2 allows to draw shapes thanks to
# Libraries library(packcircles) library(ggplot2) # Create data data <- data.frame(group=paste("Group", letters[1:20]), value=sample(seq(1,100),20)) # Generate the layout. This function return a dataframe with one line per bubble. # It gives its center (x and y) and its radius, proportional of the value packing <- circleProgressiveLayout(data$value, sizetype='area') # We can add these packing information to the initial data frame data <- cbind(data, packing) # Check that radius is proportional to value. We don't want a linear relationship, since it is the AREA that must be proportionnal to the value # plot(data$radius, data$value) # The next step is to go from one center + a radius to the coordinates of a circle that # is drawn by a multitude of straight lines. dat.gg <- circleLayoutVertices(packing, npoints=50) # Make the plot ggplot() + # Make the bubbles geom_polygon(data = dat.gg, aes(x, y, group = id, fill=as.factor(id)), colour = "black", alpha = 0.6) + # Add text in the center of each bubble + control its size geom_text(data = data, aes(x, y, size=value, label = group)) + scale_size_continuous(range = c(1,4)) + # General theme: theme_void() + theme(legend.position="none") + coord_equal()