[R] adding labels above bars in a barplot

Fri Sep 10 20:40:47 CEST 2010

Are you trying to say that you don't really like barplots?????

At least the OP did not ask for error bars as well.  :)

--- On Fri, 9/10/10, Dennis Murphy <djmuser at gmail.com> wrote:

> From: Dennis Murphy <djmuser at gmail.com>
> Subject: Re: [R] adding labels above bars in a barplot
> To: "Antonio Olinto" <aolinto_r at bignet.com.br>
> Cc: "R-help" <R-help at stat.math.ethz.ch>
> Received: Friday, September 10, 2010, 2:31 PM
> Hi:
> 
> To add to Greg's sound advice, if you want to put the
> numbers on top of the
> bars, why bother with the numerical scale? The entire point
> of a scale is to
> provide a reference for comparing different (sets of)
> values.
> 
> \begin{rant}
> And when I see things like this:
> > dat.bar
> >              VAR1
> > Category 01 17.5
> > Category 02 15.2
> > Category 03 10.3
> > Category 04  8.4
> > Category 05 20.3
> 
> I get doubly annoyed, because it is yet another attempt to
> use a bar chart
> to plot quantitative values by factor level. As I mentioned
> in a private
> response today, one of the problems with a bar chart is
> that it forces the
> numerical scale to have origin zero, and this is often
> neither necessary nor
> desirable. A simple line plot that connects the
> quantitative values between
> categories is sufficient, and takes *far* less ink to
> produce. The purpose
> of a statistical graphic is to convey information in a
> simple, clean,
> concise fashion - it is not meant to be a rococo art form.
> If you intend to
> write a function to automate a graphic, please think
> carefully about what is
> meant to be conveyed and the *visually* simplest means by
> which to convey
> it.
> \end{rant}
> 
> The purpose of a bar chart is to visualize a (joint)
> discrete distribution.
> There are better ways to plot quantitative variables by
> group; in addition
> to the line plot mentioned above, the Cleveland dot chart
> can be very
> effective with many groups or multiple grouping factors.
> With two factors
> and a quantitative response, another option is the
> interaction plot.
> 
> If this weren't the third such example/request I've seen
> today, I probably
> wouldn't be so apoplectic...
> 
> Dennis
> 
> On Fri, Sep 10, 2010 at 10:44 AM, Greg Snow <Greg.Snow at imail.org>
> wrote:
> 
> > See this message and the replies to it (and the
> replies to the replies,
> > etc.):
> >
> > http://tolstoy.newcastle.edu.au/R/e2/help/07/08/22858.html
> >
> > In there is a discussion of why you don't really want
> to do that along with
> > better alternatives and examples of the improved
> plots.
> >
> > --
> > Gregory (Greg) L. Snow Ph.D.
> > Statistical Data Center
> > Intermountain Healthcare
> > greg.snow at imail.org
> > 801.408.8111
> >
> >
> > > -----Original Message-----
> > > From: r-help-bounces at r-project.org
> [mailto:r-help-bounces at r-
> > > project.org] On Behalf Of Antonio Olinto
> > > Sent: Friday, September 10, 2010 8:59 AM
> > > To: R-help
> > > Subject: [R] adding labels above bars in a
> barplot
> > >
> > > Hello,
> > >
> > > I want to make a general routine to draw barplots
> with numbers plotted
> > > above each bar. See the example below.
> > >
> > > I could not place the numbers on the middle of
> each bar because I
> > > could not calculate the right position of each
> x-axis tick. axTicks(1)
> > > indicated a unitary step, but it does not seem
> work.
> > >
> > > I appreciate any help or suggestions.
> > >
> > > Best regards,
> > >
> > > Antonio Olinto
> > >
> > > ======================
> > >
> > > CAT   VAR1    VAR2
> > > Category 01   17.5    9
> > > Category 02   15.2   
> 20
> > > Category 03   10.3   
> 500
> > > Category 04   8.4 
>    150
> > > Category 05   20.3   
> 5000
> > >
> > > # Coping data from a spreadsheet
> > >
> > > dat.data <- read.delim("clipboard",header=T)
> > >
> > > summary(dat.data)
> > >           
> CAT         VAR1   
>         VAR2
> > >   Category
> 01:1   Min.   :
> 8.40   Min.   :   9
> > >   Category
> 02:1   1st Qu.:10.30   1st
> Qu.:  20
> > >   Category
> 03:1   Median :15.20   Median
> : 150
> > >   Category
> 04:1   Mean   :14.34   Mean   :1136
> > >   Category
> 05:1   3rd Qu.:17.50   3rd
> Qu.: 500
> > >             
>  
>    Max.   :20.30   Max.   :5000
> > >
> > > dat.bar <- data.frame(dat.data[,c(2)])
> > > row.names(dat.bar)<-dat.data[,1]
> > > names(dat.bar)<-c("VAR1")
> > > dat.bar
> > >             
> VAR1
> > > Category 01 17.5
> > > Category 02 15.2
> > > Category 03 10.3
> > > Category 04  8.4
> > > Category 05 20.3
> > >
> > > par(mar=c(12,6,3,2),cex.axis=1.2,cex.lab=1.4)
> > >
> barplot(t(as.matrix(dat.bar)),ylim=c(0,max(dat.data[,2]*1.1)),las=2,yla
> > > b="Y
> > > label text",col="orange")
> > > box()
> > >
> > > up <- max(dat.data$VAR1)*0.1
> > >
> > > for (i in c(0:nrow(dat.data))) {
> > >
> legend(0.25+i,dat.bar[1+i,1]+up,dat.data[i+1,3],col="blue",bty="n")
> > > }
> > >
> > >
> > >
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> > >
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> > R-help at r-project.org
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> 
> ______________________________________________
> R-help at 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
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> reproducible code.
> 