I would use the my.symbols function from the TeachingDemos package
(but then I might be a little bit biased), here is a simple example:
library(TeachingDemos)
x <- runif(25)
y <- runif(25)
z <- sample(1:4, 25, TRUE)
ms.halfcirc2 <- function(col, adj=pi/2, ...) {
theta <- seq(0, 2*pi, length.out=300)+adj
x <- cos(theta)
y <- sin(theta)
if(col==1) {
polygon(x,y)
} else if(col==2) {
polygon(x,y, col='red')
} else if(col==3) {
polygon(x,y, col='blue')
} else {
polygon(x[1:150], y[1:150], border=NA, col='red')
polygon(x[151:300], y[151:300], border=NA, col='blue')
polygon(x,y)
}
}
my.symbols( x, y, ms.halfcirc2, inches=1/5, add=FALSE,
symb.plots=TRUE, col=z)
# spice it up a bit
my.symbols( x, y, ms.halfcirc2, inches=1/5, add=FALSE,
symb.plots=TRUE, col=z, adj=runif(25, 0, pi))
Adjust things to fit better what you want.
On Tue, Mar 27, 2012 at 8:49 PM, alan <alan.wu2...@gmail.com> wrote:
> I want to plot many points and want to use circles. The filling color
> depends on variable a. if a=1, then not fill
> if a=2 then fill with red, if a=3 then fill with blue, if a=4, fill
> half with red and half with blue. Can anyone tell me how to plot the
> case "a=4"? Thanks a lot
>
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
--
Gregory (Greg) L. Snow Ph.D.
538...@gmail.com
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and provide commented, minimal, self-contained, reproducible code.
