Great, I don't know how I missed that, thanks! baptiste
On Sep 23, 2010, at 10:39 AM, Deepayan Sarkar wrote: > On Thu, Sep 23, 2010 at 12:33 PM, baptiste auguie > <baptiste.aug...@googlemail.com> wrote: >> Dear list, >> >> I'm using lattice::levelplot to plot a coloured image of 3D data. The >> range of the z values goes from negative to positive, but is not >> exactly centred around 0. I would however like to map a diverging >> colour scale with white falling exactly at 0, and both extremes being >> symmetrical in the legend to better contrast the opposite change in >> colour saturation. The following dummy example illustrates my problem, >> >> >> library(lattice) >> d <- transform(expand.grid(x=seq(0, 10, length=100), >> y=seq(0, 10, length=100)), >> z = sin(x/pi)*cos(0.5*y/pi) - 0.2) >> >> levelplot(z~x*y, data=d, >> panel=panel.levelplot.raster, >> cuts = 100, interpolate = TRUE) >> >> The colour scale goes from -0.3 to 0.9 with a middle (white) value of >> 0.3 approximately. I'd like it to be from -1 (most saturated blue) to >> 1 (most saturated pink), say, with 0 being white. >> >> I read the entry in ?levelplot and in ?level.colors but could not find >> a solution to this particular case. > > Specify the cut-points explicitly: > > levelplot(z~x*y, data=d, panel = panel.levelplot.raster, at = > do.breaks(c(-1, 1), 100)) > > -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.
