On Thu, May 7, 2009 at 12:02 PM, Greg Snow <greg.s...@imail.org> wrote: > From the help for panel.levelplot in the section on 'col.regions': > > " the exact number being one > more than the length of 'at'" > > was what I based my assumption on (also the "not longer than at" phrase in > the last sentence on recycling).
Thanks, that's definitely a documentation bug. I've reorganized the documentation for levelplot colors (hopefully for the better). Should show up in the next update. -Deepayan > > The second part was somewhat speculation on my part, automatically adding > -Inf and Inf would mean that you would not need to make sure to span the > range of the data, but on the other hand, it would make it hard to exclude > values outside the region as in your example, arguments could be made for > either direction, the current behavior is probably best overall. > > -- > Gregory (Greg) L. Snow Ph.D. > Statistical Data Center > Intermountain Healthcare > greg.s...@imail.org > 801.408.8111 > > >> -----Original Message----- >> From: Deepayan Sarkar [mailto:deepayan.sar...@gmail.com] >> Sent: Wednesday, May 06, 2009 6:35 PM >> To: Greg Snow >> Cc: Antje; r-h...@stat.math.ethz.ch >> Subject: Re: [R] levelplot question >> >> On Tue, May 5, 2009 at 8:58 AM, Greg Snow <greg.s...@imail.org> wrote: >> > The function that is doing the color assignments is level.colors in >> the lattice package. >> > Looking at the code confirms that the number of colors should be 1 >> less than the length >> > of the at variable (the documentation implies that it should be 1 >> more, looks like a documentation bug to me). >> >> Could you point to the place where this is implied? I couldn't see >> anything obviously wrong in ?levelplot or ?level.colors. >> >> > It is possible that at one time the author intended to prepend -Inf >> and append Inf to the at >> > vector so that it did not need to span the entire range of the data, >> but that was not implemented. >> > I think I would prefer that fix to changing the documentation. >> >> That is a slightly different issue though: e.g., >> >> > level.colors(c(1, 2, 3), at = c(1.5, 2.5, 3.5), colors = FALSE) >> [1] NA 1 2 >> >> The first value doesn't fall in any interval, so gets a NA. >> >> level.colors() is mainly a helper function for levelplot(), and it is >> important there that the first and last intervals not be open-ended. >> levelplot() has no 'zlim' argument, and you need 'at' to restrict the >> values shown, e.g., >> >> levelplot(volcano, at = do.breaks(c(120, 200), 10)) >> >> -Deepayan > ______________________________________________ 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.
