Make a map with ggplot2

makeMap takes in two sources of data that refer to geographical regions and merges them together. Depending on the arguments passed, it returns this merged data or a ggplot object constructed with the data.

makeMap(
  data = NULL,
  map = NULL,
  key = c(key.data, key.map),
  key.data,
  key.map,
  tr.data = identity,
  tr.map = identity,
  plot = c("borders", "frame", "none")
)

Arguments

data

A dataframe with regions as cases

map

An object that can be fortified to a dataframe (ex: a dataframe itself, or a SpatialPolygonsDataFrame)

key

The combination of key.data and key.map

key.data

The column name in the data that holds the unique names of each region

key.map

The column name in the map that holds the unique names of each region

tr.data

A function of the transformation to be performed to the key.data column

tr.map

A function of the transformation to be performed to the key.map column

plot

The plot desired for the output. plot = "none" returns the merged data that is the result of merging the data and map together; plot="frame" returns an empty (unplottable) ggplot object; plot = "border" (the default) returns a ggplot object with one geom_polygon layer that shows the borders of the regions.