# coordinate geografiche, densità di popolazione
# es.: 0.117208*10^6 popolaz., area 3262 in km^2
cerchio <- function(x,cit) {r <- sqrt(x[3])/25
  symbols(x[1],x[2],circles=r,inches=FALSE,add=TRUE,fg="red")
  text(x[1],x[2],cit,font=2) }
plot(c(7,14),c(41.3,46.5),type="n",asp=1)
abline(h=axTicks(2),v=axTicks(1),lty=3,col="grey60")
aosta <- c(7.31,45.75,0.117208*10^6/3262)
trentino <- c(11.12,46.08,0.934731*10^6/13618)
piemonte <- c(7.68,45.08,4.338*10^6/25399)
lombardia <- c(9.17,45.47,8.941*10^6/23859)
veneto <- c(12.33,45.43,4.453*10^6/18364)
liguria <- c(8.93,44.42,1.702*10^6/5418)
toscana <- c(11.24,43.78,3.599*10^6/22992)
e_romagna <- c(11.34,44.5,3.984*10^6/22123)
umbria <- c(12.39,43.11,0.822972*10^6/8456)
marche <- c(13.5,43.6,1.447*10^6/9693)
lazio <- c(12.5,41.89,5.146*10^6/17203)
cerchio(aosta,"ao"); cerchio(trentino,"tr"); cerchio(piemonte,"pi")
cerchio(veneto,"ve"); cerchio(lombardia,"lo"); cerchio(liguria,"li")
cerchio(toscana,"to"); cerchio(e_romagna,"er"); cerchio(umbria,"um")
cerchio(marche,"ma"); cerchio(lazio,"la")