labelCountries: to print country labels on a world map

Description

Given no arguments it will print country names stored in the 'NAME' column of getMap onto an existing map at the centroids of each country polygon, stored in the 'LAT' and 'LON' columns. Alternatively the user can specifiy a data frame or SpatialPolygonsDataFrame in which case they need to define the column containing the country names (nameCountryColumn) and optionally a 2nd attribute column to print (nameColumnToPlot). First you need to create a map plot, for example using mapCountryData or mapBubbles.

Usage

labelCountries(
  dF = "",
  nameCountryColumn = "NAME",
  nameX = "LON",
  nameY = "LAT",
  nameColumnToPlot = "",
  col = "grey",
  cex = 0.8,
  ...
)

Value

nothing

Arguments

dF: dataframe or SpatialPolygonsDataFrame
nameCountryColumn: name of column containing country names to be printed on the map (could also be set to any other column in the dataframe)
nameX: name of column containing the X variable (longitude), not needed if dF is a SpatialPolygonsDataFrame
nameY: name of column containing the Y variable (lattitude), not needed if dF is a SpatialPolygonsDataFrame
nameColumnToPlot: name of an attribute column in the data frame the value of which will be appended to the country names
col: colour for labels, default 'grey', can be e.g. rgb(1,1,0,alpha=0.5)
cex: sizing of labels, default = 0.8
...: other parameters that can be passed to text(), e.g. pos=4 to right, (1=below, 2=left, 3=above)

Author

andy south

Examples

Run this code


mapCountryData()
labelCountries()

labelCountries(nameColumnToPlot = "POP_EST")