R help - Oct 2007 - ylim in barplot2 function?

Hi list,

I'm using barplot2 form the gplots package to plot a few numbers (I want to
add SD bars later).

However, I would like the y-axis not to start from 0 but 500. When I add the
parameters YLIM, something goes wrong. The graph is not 'cut off' at
500. Instead the bars seems to sink trough the bottom of the graph.

Because its a little hard to explain, here is a self-containing example:


library(gplots)

ABrt<-c(588,589,593,588)
Wrt<-c(580,583,592,612)

RT<-rbind(ABrt,Wrt)
barplot2(RT,beside=T,col=c('black','white'),ylim=c(500,1000))

Does anybody know of a solution?

Regards,
Dieter

------------------------------------------
Dieter Vanderelst

dieter _ vanderelst AT emailengine DOT org
d DOT vanderelst AT tue DOT nl

Eindhoven University of Technology
Faculty of Industrial Design
Designed Intelligence Group
Den Dolech 2
5612 AZ Eindhoven
The Netherlands
Tel +31 40 247 91 11

I'm not sure exactly why it won't work but it could be
that conceptually a bar plot starting at 500 does not
make a lot of sense and the package writers did not
entertain such an idea?    

I'd suggest having a look at ?dotchart as an
alternative why to plot the data or perhaps have a
look at errplot() in Hmisc.  

If you really need a barplot you might have a look at
gap.barplot in plotrix.  


--- Dieter Vanderelst
<dieter_vanderelst at emailengine.org> wrote:
> Hi list,
> 
> I'm using barplot2 form the gplots package to plot a
> few numbers (I want to add SD bars later).
> 
> However, I would like the y-axis not to start from 0
> but 500. When I add the parameters YLIM, something
> goes wrong. The graph is not 'cut off' at 500.
> Instead the bars seems to sink trough the bottom of
> the graph.
> 
> Because its a little hard to explain, here is a
> self-containing example:
> 
> 
> library(gplots)
> 
> ABrt<-c(588,589,593,588)
> Wrt<-c(580,583,592,612)
> 
> RT<-rbind(ABrt,Wrt)
>
barplot2(RT,beside=T,col=c('black','white'),ylim=c(500,1000))
> 
> Does anybody know of a solution?
> 
> Regards,
> Dieter
> 
> ------------------------------------------
> Dieter Vanderelst
> 
> dieter _ vanderelst AT emailengine DOT org
> d DOT vanderelst AT tue DOT nl
> 
> Eindhoven University of Technology
> Faculty of Industrial Design
> Designed Intelligence Group
> Den Dolech 2
> 5612 AZ Eindhoven
> The Netherlands
> Tel +31 40 247 91 11
> 
> ______________________________________________
> 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
> and provide commented, minimal, self-contained,
> reproducible code.
>

On Wed, 2007-10-31 at 11:52 +0100, Dieter Vanderelst
wrote:
> Hi list,
> 
> I'm using barplot2 form the gplots package to plot a few numbers (I
> want to add SD bars later).
> 
> However, I would like the y-axis not to start from 0 but 500. When I
> add the parameters YLIM, something goes wrong. The graph is not 'cut
> off' at 500. Instead the bars seems to sink trough the bottom of the
> graph.
> 
> Because its a little hard to explain, here is a self-containing
> example:
> 
> 
> library(gplots)
> 
> ABrt<-c(588,589,593,588)
> Wrt<-c(580,583,592,612)
> 
> RT<-rbind(ABrt,Wrt)
>
barplot2(RT,beside=T,col=c('black','white'),ylim=c(500,1000))
> 
> Does anybody know of a solution?
> 
> Regards,
> Dieter
The behavior here is the same for both barplot() and barplot2(). You
need to set par("xpd") to FALSE, so that the bars are clipped to the
plot region:

barplot2(RT,beside=T,col=c('black','white'),ylim=c(500,1000), 
         xpd = FALSE)

See ?par

That being said, this is a bad idea in general, as you impact the
ability to visually discern the relative difference (or lack of it) in
the bars. You would be better off using a dotplot.

HTH,

Marc Schwartz