[R] how to best present concentrated data points/ ggplot2

[Ista Zahn]

Hi Yang,
Strategies for dealing with overplotting include transparency, size,
and jittering. In your example you'll probably need all three.

m + geom_point(aes(x = expo, y = ze, shape = type),
  size = 1, alpha = .2,  position = position_jitter(width = 0, height
= 5)) + geom_density()

seems to work OK.

Best,
Ista

On Tue, Jul 5, 2011 at 8:46 PM, Yang Lu <Yang.Lu at williams.edu> wrote:
>
> Hi all,
>
> I am trying to plot a weighted density plot for two different types and want to show the data points on the x axis.
>
> The code is as follows. The data points are very concentrated. Is there a better way to present it( should I set the alpha value or something else)?
>
> Thanks!
>
> YL
>
> library(ggplot2)
>
> x <- rnorm(10000)
>
> a <- rnorm(5000)
>
> b <- rnorm(5000)
>
> weights.x <- abs(a/sum(a))
>
> weights.y <- abs(b/sum(b))
>
> weight <- c(weights.x, weights.y)
>
> ze <- rep(0,10000)
>
> type <- c(rep("a",5000), rep("b",5000))
>
> d <- data.frame(expo = x, weight = weight, type = type, ze = ze)
>
> m <- ggplot(d, aes(x = expo, group = type, col = type, weight = weight))
>
> m+geom_density()+geom_point(aes(x = expo, y = ze, shape = type))
>
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--
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org