Júlio, Your code is not reproducible, you doesn't provide any data. So I did a minimal code that illustrates a possible procedure is the following
n <- 30 da <- data.frame(x=runif(n), y=runif(n), z=runif(n)) da$z <- cut(da$z, seq(0,1,0.25)) require(lattice) xyplot(y~x, da, cex=as.numeric(da$z), col=1, key=list(points=list(cex=1:4, pch=1), text=list(levels(da$z)), columns=4)) Bests, Walmes. ========================================================================== Walmes Marques Zeviani LEG (Laboratório de Estatística e Geoinformação, 25.450418 S, 49.231759 W) Departamento de Estatística - Universidade Federal do Paraná fone: (+55) 41 3361 3573 VoIP: (3361 3600) 1053 1173 e-mail: wal...@ufpr.br twitter: @walmeszeviani homepage: http://www.leg.ufpr.br/~walmes linux user number: 531218 ========================================================================== [[alternative HTML version deleted]]
______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.