I was working on making a map in R recently and after an extensive search online, I found a hundred different ways to do it and yet each way didn’t work quite right for my data and what I wanted to do. Eventually, I found a way to make it work after pulling together code from this blog , this blog , and this stack overflow page . Combining all of those sources, along with a good amount of trial and error, has led to this blog post.
This post shows how to use ggplot to map a choropleth map from shapefiles, as well as change legend attributes and scale, color, and titles, and finally export the map into an image file.
We need a number of packages to make this work, as you can see below so make sure to install and load those. We load in shapefiles using the readShapeSpatial() function from the maptools library. A shapefile is a geospatial vector data storage format for storing map attributes like latitude and longitude. You can download lots of shape files for free! For example, for any country in the world you can download shape files here . Or just google it.