On Sat, Sep 12, 2009 at 1:34 PM, Stephan Kolassa <stephan.kola...@gmx.de> wrote: > Dear guRus, > > I am starting to work with the ggplot2 package and have two very dumb > questions: > > 1) deterministic position_jitter - the jittering is stochastic; is there any > way to get a deterministic jittering? For instance: > > example.data <- > data.frame(group=c("foo","bar","foo","bar","foo","bar"),x=c(1,1,2,2,3,3),y=c(1,1,0,2,1,1)) > set.seed(2009) > qplot(x,y,data=example.data,shape=group,position=position_jitter(w=0.1,h=0)) > > For x=1, the foo point is to the left of the bar point, and for x=3 the > other way around. I would like to have all foo points at seq(1,3)-epsilon > and all bar points at seq(1,3)+epsilon. Do I need to manually modify > example.data$x groupwise for this?
Yes. The plyr package generally makes this sort of manipulation pain free. > 2) geom_line with position_jitter - when I call multiple geoms with > position_jitter, each geom gets its own jittering. For example (continuing > with example.data above): > > set.seed(2009) > qplot(x,y,data=example.data,geom=c("point","line"),shape=group,position=position_jitter(w=0.1,h=0)) > > The lines do not connect the points - is there any way to have the geom_line > connect all the foo points on the one hand and all the bar points on the > other hand? Again, you'll have to adding the jittering yourself. > -------------------------------------------------------------- > > What I've done: searched through HW's book, googled, searched RSeek. For > point 2) above, I tried using multiple layers and resetting the seed in > between, to wit: > > pp <- ggplot(example.data,aes(x,y,shape=group)) > set.seed(2009) > pp <- pp+layer(geom="point",position=position_jitter(w=0.1,h=0)) > set.seed(2009) > pp <- pp+layer(geom="line",position=position_jitter(w=0.1,h=0)) > print(pp) > > This doesn't do what I want, either... The jittering isn't evaluated until render time, so this won't help. You'll notice if you draw the plot again, you'll get a different rendering. Hadley -- http://had.co.nz/ ______________________________________________ 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.