depthgroup <- equal.count(quakes$depth, number=3, overlap=0) trellis.par.set(theme = canonical.theme("postscript", col=FALSE)) trellis.par.set(list(dot.symbol=list(pch=1), axis.text=list(cex=0.7))) temp <- xyplot(lat ~ long | depthgroup, data=quakes, pch=".", layout=c(3, 1)) print(temp, panel.width=list(1.21, "inches"), panel.height=list(1.5, "inches"))