[R] axis in an image() plot

[Jim Lemon]

Ricardo Rodríguez - Your XEN ICT Team wrote:
> Hi all,
> 
> I've found quite usefull colored-grid created by image() but I'm facing a doubt I am not able to solve.
> 
> Given the following data rectangle...
> 
>          1  2  3  4  5  6  7  8  9 10 11 12 13 14
>       1 12 22  0  7  2  1  0  2  0  2  6 -3  0  3
>       2  0 -1  0  9  3 -4  0  0  0  0  3  0  0  0
>       3 29 45  6 12 16 85 -2  0 -3 -4 89 -1 -1  1
>       4  2  9  3  6 17  3 -2 -9 -2  8 -1  0  0  0
>       5 44 16 -3 21 23  3  2  1  0 -2 13 18 -5  2
> 
> I am not able to draw x and y axis labeled 1 to 14 and 1 to 5 by 1. I've tried a number of options by using axis() to no avail.
> 
> It will be also very helpfull to be able to draw the value of each x,y combination within its position in the grid. Text() seems to be the answer, but I am not able yet to get the correct position for each label.
> 
> Please, could you point me in the right direction or offer some example?
> 
Hi Ricardo,

This might be what you want (say your data frame is called my.df):

library(plotrix)
color2D.matplot(my.df,c(1,0),c(0,0),c(0,1))
text(rep(0.5:13.5,5),rep(seq(4.5,0.5,by=-1),14),
  unlist(my.df),col="white")

and in fact it looks so neat that I might add it as an option.

Jim