##tmap

library(tmap)
tm_shape(World)+ 
  tm_polygons(
    fill = "#A52A2A", # fill color
    col = "black",    # line color
    lwd = 0.5,        # line width
    lty = "dashed")   # line type
## [tip] Consider a suitable map projection, e.g. by adding `+ tm_crs("auto")`.
## This message is displayed once per session.

##Data-driven symbol

tm_shape(World)+ 
  tm_polygons(fill = "grey90") +   # constant fill color 
  tm_symbols(size = "pop_est",     # data variable, mapped to symbol size
             fill = "well_being",  # data variable, mapped to symbol fill color
             shape = "income_grp") # data variable, mapped to symbol shape