[R] different color indicates difference magnitude

[Marc Girondot]

> On 13/03/13 10:20, meng wrote:
>> Hi all:
>> Is there a plot tool to use different color indicates difference 
>> magnitude of data?
>> The plot is in the attachment.
>>
>> Many thanks.
No sure what you want exactly as there is no attachment here.
Here are an example of what can be done:

x <- 1:128
y <- rnorm(128, 10, 2)

z <- x+y

nbcol <- heat.colors(128)

# standardize z to be from 1 to 128
zcol <-  ((z-min(z))/(max(z)-min(z)))*127+1

# different examples
plot(x, y, col=nbcol[zcol], pch=".", cex=10, bty="n")
plot(x, y, col=nbcol[zcol], pch=".", cex=zcol/10, bty="n")
plot(x, y, col=nbcol[128-zcol], pch=".", cex=10, bty="n")

Sincerly

Marc


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