Dear R-help, I recently discovered lattice xyplot, but have been struggling with plotting a second y-axis. I am able to do this with plot() but can't figure it out in xyplot. Any help would be appreciated. I have found help on adding a second Y-axis when the data is all part of the same data frame, but I have two different data frames. Both data sets are being plotted against "Date". However the first data set only plots a few points on select dates whereas the second data set is plotted daily. I would like to plot them both with the same x-axis, but separate (labeled) y-axes. Is this possibly in lattice xyplot without too much hassle? Or am I better off plotting with plot()?
#The first data set plot: trellis.par.set(superpose.symbol = list(cex = 1.3, pch = c(15,0,17,2), col=c("blue","blue","red","red")) ) xyplot(melt ~ Date, data = df1, groups = si, col = c("blue","blue","red","red"), pch= c(15,0,17,2), type = 'p', auto.key = list(points = TRUE, lines = FALSE, x=0.8, y=0.15, corner = c(0,1)) ) #The second data set plot: xyplot(AT ~ Date, data = df2, type = 'o', lty = 1, col = "black" ) Example data: #df1: Date <- as.Date(rep(c("2008-04-27","2008-05-02"),each=4), format="%Y-%m-%d") si <- factor(rep(c("SO","SF","NO","NF"),2)) melt <- c(4.7,7.4,17.8,30.8,2.2,11.7,10.1,17.3) df1 <- data.frame(Date, si, melt) #df2: Date <- as.Date(c("2008-04-27","2008-04-28","2008-04-29","2008-04-30","2008-05-01","2008-05-02"), format="%Y-%m-%d") AT <- c(7.4,4.5,3.2,2.1,2.0,1.1) df2 <- data.frame(Date,AT) Thank you very much for your time. Kara ______________________________________________ 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.