So far we have used the default appearance for addPolygons(). There are several more ways to customize the polygons.

The arguments to addPolygons() we will focus on are:

weight: the thickness of the boundary lines in pixels
color: the color of the polygons
label: the information to appear on hover
highlightOptions: options to highlight a polygon on hover

addPolygons(weight = 2,
           color = "red",
           label = ~paste0("Total Income: ", dollar(income)),
           highlight = highlightOptions(weight = 10,
                                       color = "blue",
                                       bringToFront = TRUE))

The high_inc SpatialPolygonsDataFrame you created in the previous exercise has been loaded for you.