There's more...

over-plotting is commonly associated with the point geometry. So far this chapter demonstrated three different ways to deal with it, bu these are not the only solutions. Another feasible solution is to set an alternative geometry that does not suffer with over-plotting, for example hexagonal heatmaps:

> library(ggplot2)
> sca5 <- ggplot(diamods, aes( x = carat, y = price))
> sca5 + geom_hex()

Resulting outcome is a hexagonal heatmap drawn over a diamonds data set; it's supposed to work as a little tease to what is going to be seen later in this book. There will always be downsides and upsides of choosing one over another. Each situation will call for one or more types of solutions. Now that you know a few, it's up to you to choose the one that suits you best.