Limits in scales set values outside the limits to NA. Hence the boxplots, smoothers,... change. Use coord_cartesian() to "zoom in".
Op 20-jul.-2015 20:29 schreef "Jacob Wegelin" <jacobwege...@fastmail.fm>: > > With base graphics, one can use the "ylim" argument to zoom in on a boxplot. > > With ggplot2, using "limits" to try to zoom in on a boxplot *changes the box*. Since the box usually indicates the 25th and 75th percentiles of a quantitative variable, this is puzzling. > > The toy code below demonstrates this. In ggplot2, "zooming in" causes the two boxes to overlap, when they did not overlap in the full plot. Also, the center lines --- which usually indicate the median of the variable --- change when one zooms in. > > In base graphics, "zooming in" does not cause the boxes to overlap or, as far as I can see, the median line to move relative to the scale. > > What is going on here? > > pdf(file="toy-example.pdf") > set.seed(1) > toy1<-data.frame(Y=rnorm(500, mean=3), A="one") > toy2<-data.frame(Y=rnorm(500, mean=1.6), A="two") > toy<-rbind(toy1,toy2) > toy$A<-factor(toy$A) > library(ggplot2) > mybreaks<-signif(seq(from=min(toy$Y),to=max(toy$Y),by=0.5),digits=2) > mylimits<-c(0.61,3.7) > print(myplot<-ggplot(toy, aes(x=A,y=Y)) + geom_boxplot()+scale_y_continuous(breaks=mybreaks)+theme_bw()) > print(myplot+scale_y_continuous(breaks=mybreaks,limits=mylimits)) > boxplot(toy1$Y,toy2$Y) > boxplot(toy1$Y,toy2$Y, ylim=mylimits) > graphics.off() > >> sessionInfo() > > R version 3.2.1 (2015-06-18) > Platform: x86_64-apple-darwin13.4.0 (64-bit) > Running under: OS X 10.10.4 (Yosemite) > > locale: > [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8 > > attached base packages: > [1] stats graphics grDevices utils datasets methods base > > other attached packages: > [1] ggplot2_1.0.1 > > loaded via a namespace (and not attached): > [1] MASS_7.3-40 colorspace_1.2-6 scales_0.2.5 magrittr_1.5 plyr_1.8.3 tools_3.2.1 gtable_0.1.2 reshape2_1.4.1 > [9] Rcpp_0.11.6 stringi_0.5-5 grid_3.2.1 stringr_1.0.0 digest_0.6.8 proto_0.3-10 munsell_0.4.2 > > > Jacob A. Wegelin > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
