R help - Aug 2007 - Stacked Bar

Hi R Users!
 
Thanks in advance.
 
I am using R-2.5.1 on Windows XP.
 
I am trying to do a stacked bar plot, but could not get through the following
problem. The code is given below.
   
  1. How can I provide 15 different colors for each method with 15 Rows?
   
  2. How can I put the legend in a particular position (eg., in the top or
bottom or right or left)? How can I put legend using a number of rows (eg.,
using two or three rows)?
  
Once again thank you very much for your time.
 
Regards,
 
Debabrata (Deb)
Statistician
NSW Department of CommerceSydney, Australia.

  The Code:
   
  library(lattice)
library(graphics)
   
  x <- matrix(1:75, ncol= 5)
dimnames(x)[[2]] <- paste("Method", 1:5, sep="")
dimnames(x)[[1]] <- paste("Row", 1:15, sep="")
   
  # library: graphics
   
  barplot(x,
        beside=FALSE,
        col= 1:nrow(x),        
        legend= rownames(x)        
       )
   
  # library: lattice
   
  barchart(Freq ~ Var2,
         data = as.data.frame.table(x),
         groups = Var1, stack = TRUE,
         auto.key = TRUE)
   

       
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Deb Midya wrote:
> Hi R Users!
>  
> Thanks in advance.
>  
> I am using R-2.5.1 on Windows XP.
>  
> I am trying to do a stacked bar plot, but could not get through the
following problem. The code is given below.
>    
>   1. How can I provide 15 different colors for each method with 15 Rows?
>    
>   2. How can I put the legend in a particular position (eg., in the top or
bottom or right or left)? How can I put legend using a number of rows (eg.,
using two or three rows)?
>   
Hi Deb,
As you have probably noticed, the integer coded colors repeat too 
quickly for the number of colors you want. You can use the rainbow()
function to generate colors like this:

barplot(x,beside=FALSE,col=rainbow(nrow(x)))

or there are lots of other color generating functions in the grDevices 
or plotrix packages. Here's how to get your legend in an empty space for 
your plot. There is also an emptyspace() function in the plotrix package 
that tries to find the biggest empty space in a plot, although it 
probably wouldn't work in this case.

legend(0,1000,rownames(x),fill=rainbow(nrow(x)))

Jim

Deb,

Others have answered your question, I just want to give you something
else to think about.

Stacked bar plots may not be the best tool to use for this situation,
they are ok for comparing the bottom and top groups, but all the other
groups don't line up in a stacked bar plot making those comparisons
harder.  The fact that you want 15 different colors means that this is
even more likely the case.  You also need to be careful that your colors
are different enough from each other that they can be easily
distinguished (even when a bar or 2 between them is so small as to not
appear).

You may want to consider dotplots as an alternative, you can use symbols
(possibly numbers or initial letters) in place of or along with the
colors.  You can also format the dotplot so that the most interesting
comparisons are the easiest to make.  See the dotplot function in the
lattice package and the dotchart2 function in the Hmisc package.

If you send us more detail on what you are trying to show (maybe even
some simulated data in the same form as your real data), then we can
give additional suggestions on how to display the data.

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at intermountainmail.org
(801) 408-8111
 
 
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Deb Midya
> Sent: Tuesday, August 21, 2007 5:29 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] Stacked Bar
> 
> Hi R Users!
>  
> Thanks in advance.
>  
> I am using R-2.5.1 on Windows XP.
>  
> I am trying to do a stacked bar plot, but could not get 
> through the following problem. The code is given below.
>    
>   1. How can I provide 15 different colors for each method 
> with 15 Rows?
>    
>   2. How can I put the legend in a particular position (eg., 
> in the top or bottom or right or left)? How can I put legend 
> using a number of rows (eg., using two or three rows)? 
>   
> Once again thank you very much for your time.
>  
> Regards,
>  
> Debabrata (Deb)
> Statistician
> NSW Department of CommerceSydney, Australia.
> 
>   The Code:
>    
>   library(lattice)
> library(graphics)
>    
>   x <- matrix(1:75, ncol= 5)
> dimnames(x)[[2]] <- paste("Method", 1:5, sep="") 
> dimnames(x)[[1]] <- paste("Row", 1:15, sep="")
>    
>   # library: graphics
>    
>   barplot(x,
>         beside=FALSE,
>         col= 1:nrow(x),        
>         legend= rownames(x)        
>        )
>    
>   # library: lattice
>    
>   barchart(Freq ~ Var2,
>          data = as.data.frame.table(x),
>          groups = Var1, stack = TRUE,
>          auto.key = TRUE)
>    
> 
>        
> ---------------------------------
> Park yourself in front of a world of choices in alternative vehicles.
> 
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> 
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