[R] ggplot2 geom_boxplot limits

[Thierry Onkelinx]

Here is the answer: http://rpubs.com/INBOstats/zoom_in

ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature and
Forest
team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance
Kliniekstraat 25
1070 Anderlecht
Belgium

To call in the statistician after the experiment is done may be no more
than asking him to perform a post-mortem examination: he may be able to say
what the experiment died of. ~ Sir Ronald Aylmer Fisher
The plural of anecdote is not data. ~ Roger Brinner
The combination of some data and an aching desire for an answer does not
ensure that a reasonable answer can be extracted from a given body of data.
~ John Tukey

2015-07-20 22:19 GMT+02:00 Jacob Wegelin <jacobwegelin op fastmail.fm>:

> On 2015-07-20 Mon 15:19, Thierry Onkelinx wrote:
>
>>
>> Limits in scales set values outside the limits to NA. Hence the boxplots,
>> smoothers,... change. Use coord_cartesian() to "zoom in".
>>
>
> Thanks. What do I do if I also want to use coord_flip(), that is, if I
> want the boxes to lie horizontally *and* to zoom in?
>
> myplot+coord_cartesian(ylim=mylimits) # zooms in
>
> myplot+coord_cartesian(ylim=mylimits) + coord_flip() # flips but does not
> zoom
>
> myplot + coord_flip()+coord_cartesian(ylim=mylimits) # zooms but does not
> flip
>
> Jacob Wegelin
>
>
>  Op 20-jul.-2015 20:29 schreef "Jacob Wegelin" <jacobwegelin op 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 op 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.
>>
>>
>>

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