R/coords2continent.R

In karinorman/biodivTS: What the Package Does (One Line, Title Case)

# The single argument to this function, points, is a data.frame in which:
#   - column 1 contains the longitude in degrees
#   - column 2 contains the latitude in degrees
coords2continent = function(points){
  countriesSP <- rworldmap::getMap(resolution='low')
  #countriesSP <- getMap(resolution='high') #you could use high res map from rworldxtra if you were concerned about detail

  # converting points to a SpatialPoints object
  # setting CRS directly to that from rworldmap
  pointsSP = sp::SpatialPoints(points, proj4string = sp::CRS(sp::proj4string(countriesSP)))


  # use 'over' to get indices of the Polygons object containing each point
  indices = sp::over(pointsSP, countriesSP)

  #indices$continent   # returns the continent (6 continent model)
  #indices$REGION   # returns the continent (7 continent model)
  indices$ADMIN  #returns country name
  #indices$ISO3 # returns the ISO3 code
}