6 Maps

Plotting geospatial data is a common visualisation task, and one that requires specialised tools. Typically the problem can be decomposed into two problems: using one data source to draw a map, and adding metadata from another information source to the map. This chapter will help you tackle both problems. I’ve structured the chapter in the following way: Section 6.1 outlines a simple way to draw maps using geom_polygon(), which is followed in Section 6.2 by a modern “simple features” (sf) approach using geom_sf(). Next, Sections 6.3 and 6.4 discuss how to work with map projections and the underlying sf data structure. Finally, Section 6.5 discusses how to draw maps based on raster data.