traceStrates = function(bounds,titre="",couleur='white'){
               if (length(couleur)==1) couleur=rep(couleur,38)
               plot(range(bounds[,1]),range(bounds[,2]),type="n",xlim=c(-66,-60),ylim=c(45,50),
                    main=titre,xlab="Longitude",ylab="Latitude")
               rect(-66,45,-60,50,col='brown')
               for(i in 401:439){
                   polygon(bounds[which(bornes[,1]==i),2:3],col=couleur[i-400])
               }
}