Zooming and making callouts from selected plot sections with facetzoom

We’ve already seen in these recipes how bioinformatics datasets can encompass very large scales. Genomes can be thousands of millions of bases long and contain tens of thousands of genes, taxa can have thousands of members, and biomes can have billions of individuals living in areas of a wide range of sizes. Contextual information is therefore often important in analysis and visualization; we may want to see a detail of some subset of data in its original broader context. We can do that by using plots with callout-style subplots—zoomed-in areas drawn alongside the wider data. In this recipe, we will look at using the facet zoom functionality in the ggforce package to look at an area of interest in a ggplot.

Getting ready

We’ll use the ggplot2, ggforce, palmerpenguins, and rbioinfcookbook packages for the main part of this recipe. The allele_freq and penguins datasets will be the basis...