Using the directlabels package to label the contours

If you ever try to display each contour value by the line itself using stat_density_2d(geom = 'text', aes(label = ..level..)) (or stat_contour(*)), you shall get yourself a hard time. The resulting visual might be very confusing, numbers will take over the plot like a messy zombie horde. However, there is an easy alternative achieved with directlabels package. This one package will do all the hard work for you plus your family and friends shall think of you as a great R shinobi.

Getting ready

Let's see how directlabels can be used to label contour lines. Only make sure to install directlabels package first:

> if( !require(directlabels)){ install.packages('directlabels')}

Internet connection has to be on if the package is not installed yet.

How to do it...

Let us now get started on recipe:

1. Design the desired contour plot:

> library(ggplot2)
> plot <- ggplot(data = cars, aes(x = speed, y = dist)) + 
   geom_density_2d(aes(colour = ....