1  Why Plainmaps?

There are times when a simple background map is needed. Such maps often reference well-known geographic entities such as countries and states.

Fortunately, there are generally adequate basemap outlines available for use with R. This means that you are unlikely to have to trace a map outline to create something you need.

Be warned that there are several packages (as well as built-in capabilities) that provide similar services. Some of the functions you’ll encounter with Internet searches use approaches that are now a bit outmoded.

I focus in this document on the use of boundary data from mapdata and use the functionality of GGPLOT2 to create the maps. Data overlays are done with Sitemaps functions.

There might be instances when you need to use a shapefile for the boundary data. This is the case for Hawai`i (and Alaska) where the US boundaries tend to omit these two non-contiguous states or the boundaries are too generalized to be useful for maps with a local focus. For these situations, there is an example where shapefiles are used.

The plain maps lend themselves to situations where colored areas represent data values. These are called choropleth maps. A few examples are shown here.

The package title “Plainmaps” reflects the content of this document. What’s shown here is a simple version of what’s possible using R to create maps. Often, that’s all you need. If you need more, this is, at the least, a starting point in your quest.