Composite plots: grid.arrange

I really like composite plots, where there’s a top part that describes a phenomenon and a bottom part with a synthetic time view of the overall process.
I’ve recently discovered this beautiful representation of educational differentials by gender, by Sara Lopus and Margaret Frye, and the beauty of this dataviz is that it tells a story on its own. (Click on the link for the publication)

I have used a random generated data to reproduce the graph in ggplot and used grid.arrange from gridExtra package to bind grobs, the top and bottom components.

grid.arrange(top, bottom, heights=c(10,5), widths=c(20), padding=0)

I have saved the map as a .png file png package and used rasterGrob from package grid to create a raster image graphical object.

Screen Shot 2018-08-30 at 11.26.50