When at, label chains contain duplicate at values, axis ticks are dropped. I believe this is handled incorrectly for Date ats in lattice 0.15-4 when compared to how it is handled for numeric, or for dates in base plot. This can result in mis-labelled axes in some circumstances. I have included executable examples.
R: 2.5.0 numeric base plot: plot(1:10, axes=F); axis(1, at=c(2,4,4,6), labels=letters[1:4]) shows labels a, b, d date scale in base plot: plot((as.Date("2007-01-01") + 1:10), 1:10, axes=F); axis(1, at= (as.Date("2007-01-01")+c(2,4,4,6)), labels=letters[1:4]) shows labels a, b, d numeric scale in lattice plot xyplot(1:10 ~ 1:10, scales=list(x=list(relation="free", at=c (2,4,4,6), labels=list(letters[1:4])))) shows labels a, b, d date scale in lattice plot xyplot(1:10 ~ (as.Date("2007-01-01") + 1:10) , scales=list(x=list (relation="free", at=list(as.Date("2007-01-01")+c(2,4,4,6)), labels=list(letters[1:4])))) shows labels a, b, c Since this results in label c being placed at position 6, not 4, I feel this is a bug. -Alex Brown ______________________________________________ R-help@stat.math.ethz.ch 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.