[R] ggplot2 histograms

Hadley Wickham
Tue, 30 Nov 2010 20:09:59 -0000

You may find it easier to use a frequency polygon, geom = "freqpoly".

Hadley

On Tue, Nov 30, 2010 at 2:36 PM, Small Sandy (NHS Greater Glasgow &
Clyde) <sandy.small at nhs.net> wrote:
> Hi
>
> With ggplot2 I can very easily create beautiful histograms but I would like
to put two histograms on the same plot. The histograms may be over-lapping.
> When they are overlapping the bars are shown on top of each other (so that
the overall height is the sum of the two). Is there any way to get them to
display overlapping (with smaller value in front, larger value behind) so that
the overall height is equal to the height of the largest value
>
> The following demonstrates the problem (there is probably a simple way to
generate the sequence in d1 but I don't know it and just threw this together
quickly)
>
d1<-c(1,2,2,3,3,3,4,4,4,4,5,5,5,5,5,6,6,6,6,7,7,7,8,8,9,6,7,7,8,8,8,9,9,9,9,10,10,10,10,10,11,11,11,11,12,12,12,13,13,14,15,15,16,16,16,17,17,17,17,18,18,18,18,18)
>
> d2<-c(rep("a",25), rep("b",39))
> dafr<-data.frame(d1,d2)
>
> library(ggplot)
> qplot(d1, data=dafr, fill=d2, geom='histogram', binwidth = 1)
>
> Many thanks for any help
> Sandy
>
> Sandy Small
> Clinical Physicist
> NHS Forth Valley
> and
> NHS Greater Glasgow and Clyde
>
>
>
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