Introduction to Spatial Data
We have been mapping points, but there are several spatial features that can be mapped, including polygons. In R, polygons are often stored in a SpatialPolygonsDataFrame that holds the polygon, coordinate information, and a data frame with one row per polygon.
A SpatialPolygonsDataFrame called shp
that contains the zip code boundaries for North Carolina has been loaded for you. shp
has five slots that store various types of information:
- data: data associated with each polygon
- polygons: coordinates to plot polygons
- plotOrder: order in which polygons are plotted
- bbox: bounding box for geographic data (i.e., a rectangle)
- proj4string: coordinate reference system
Let's take a closer look inside the shp
object.
This exercise is part of the course
Interactive Maps with leaflet in R
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Print a summary of the `shp` data
___(shp)