[R] Plotting a Trivial Matrix

Lorenzo Isella lorenzo.isella at gmail.com
Fri Feb 26 11:12:39 CET 2010


baptiste auguie wrote:
> Hi,
>
> A minimalist example using Grid graphics,
>
>
>
> library(RGraphics)
>
> bwImage <- function(m, cols=c("white", "black"),
>                     draw=TRUE, gp=gpar()){
>
> g <- imageGrob(nrow(m), ncol(m),
>                cols=cols[m+1], gp=gp)
>
> if(draw)
>   grid.draw(g)
> return(g)
> }
>
> m <- matrix(rnorm(200) > 0,  ncol=20)
> bwImage(m)
>
> HTH,
>
> baptiste
>
> On 26 February 2010 09:29, Lorenzo Isella <lorenzo.isella at gmail.com> wrote:
>   
>> Dear All,
>> Consider a matrix (N x N) where each entry is either zero or one (can
>> hardly get any simpler).
>> Now, I would like to plot it as a 'chessboard' where every matrix entry
>> is a black (1) or white (0) square.
>> Whatever tool I use to plot it, it should not try to interpolate the
>> data at all.
>> I found some online references
>> http://www.phaget4.org/R/image_matrix.html
>> but probably I can resort to something much simpler.
>> Can anyone provide me with a simple example I can modify later on?
>> Many thanks
>>
>> Lorenzo
>>
>> ______________________________________________
>> 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.
>>
>>     
>
>
>
>   
Thanks Augustine and Jim for the prompt reply.
You both answered my question. To avoid another post, I would simply 
like to know if something along these lines is doable also with ggplot2.
Many thanks

Lorenzo



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