12) Maps 2

📖 Lecture

We continue discussing maps in R. In particular, we use two interesting data sets:

1. IBTrACS shapefiles. We’ll use this to work with shapefiles, which is perhaps the most common format for vector data.

2. US Presidential Election Results (2020). We’ll use this data to make some choropleth maps. A choropleth map is a thematic map that is used to visualize how a variable varies across a geographic area.

📚 Reading

Read chapters 17, 18, and 19 of “Tidy Hurricanes”:

• https://www.gastonsanchez.com/R-tidy-hurricanes/5-01-maps-intro.html
• https://www.gastonsanchez.com/R-tidy-hurricanes/5-03-maps-sf.html
• https://www.gastonsanchez.com/R-tidy-hurricanes/5-04-maps-leaflet.html

🔬 Lab

• Graphing maps with "ggplot2", "sf", and "leaflet".

🎯 Objectives

• Describe the components of a shapefile.
• Import shapefiles in R.
• Make maps with shapefile data.
• Explain the concept of a “choropleth map”
• Plot a map of US counties with geom_sf().

🔔 Assignments

• Shiny App2, due 04/12