[R] Scatterplot Showing All Points

[Duncan Murdoch]

On 18/12/2007 7:31 AM, Antony Unwin wrote:
> Wayne,
> 
> Try the iplot command in iPlots.  You can then vary both the  
> pointsize and the transparency of your scatterplot interactively and  
> decide which scatterplot conveys the information best.  Sometimes  
> it's helpful to use more than one scatterplot when presenting your  
> results.
> 
> (I must admit to being very surprised that jittering and sunflower  
> plots have been suggested for a dataset of 5000 points.  Do those who  
> mentioned these methods have examples on that scale where they are  
> effective?)

Sure.  The original post said there were about 50-60 unique locations. 
This plot:

x <- rbinom(5000, 20, 0.15)
y <- rbinom(5000, 20, 0.15)
plot(x,y)

has a few more unique locations; tune those probabilities if you want it 
closer.  Due to the overlap, the distribution is very unclear.  But this 
plot

plot(jitter(x), jitter(y))

makes the distribution quite clear.

I wouldn't use the default pch if I had 50000 points, but with pch=".", 
it's not so bad even in that case.

Duncan Murdoch