[R] image question

[Charles C. Berry]

On Wed, 23 Jan 2008, Ajar wrote:

> Hi,
>
> I have a question regarding the image function. Is there a way to
> specify a separate color set for each column in the matrix?

Yes. But it will require some attention to the scaling of your matrix.

This shows how it might be done:

> mat <- matrix( runif(100), nc=10)
> image( mat + rep( 1:2, each=50),col=c(topo.colors(10),heat.colors(10)))

Add an offset to the matrix to choose a different color scheme.

Of course, the step size for the offset needs to be greater than or equal 
to the range of values that you are representing.

You will need to specify zlim to be sure this works right.

HTH,

Chuck

>
> TIA,
> ajar.
>
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Charles C. Berry                            (858) 534-2098
                                             Dept of Family/Preventive Medicine
E mailto:cberry at tajo.ucsd.edu	            UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901