library(cartography)

# Import a shapefile // this one is distributed within the package
mtq <- st_read(system.file("shape/martinique.shp", package="cartography"))

# Share of farmers in the active population
mtq$shareCS1 <- 100 * mtq$C13_CS1/mtq$C13_POP

# Set a custom color palette
cols <- carto.pal(pal1 = "wine.pal", n1 = 6)

# set plot margins
opar <- par(mar = c(0,0,1.2,0))

# Plot the communes
plot(st_geometry(mtq), col = "#5F799C", border = "white", 
     bg = "#A6CAE0", lwd = 0.5, add = FALSE)

# Plot symbols with choropleth coloration
propSymbolsChoroLayer(x = mtq, # sf object 
                      var = "C13_POP", # field used to plot the symbols sizes
                      var2 = "shareCS1", #  field used to plot the colors
                      col = cols, # symbols colors
                      inches = 0.4, # radius of the largest circle
                      method = "quantile", # discretization method (?getBreaks)
                      border = "grey50", # color of circle borders
                      lwd = 1, # width of the circle borders
                      legend.var.pos = "topright", # position of the first legend
                      legend.var2.pos = "left", # position of the second legend
                      legend.var2.title.txt =  
                        "Share of \nthe population\nworking in\nagriculture (%)", 
                      legend.var.title.txt = "Population aged\n15 and over",
                      legend.var.style = "c") # legend style

# Add a layout
layoutLayer(title="Farmers in Martinique, 2013", # title of the map
            scale = 5, # size of the scale bar
            north = TRUE, # north arrow
            col = "white",
            coltitle = "black",
            author = "cartography 2.0.0",  
            sources = "INSEE, 2016",
            frame = TRUE)

# restore graphics parameters
par(opar)