R help - Aug 2010 - drawing dot plots with size, shape affecting dot characteristics

Hi all,

I'm interested in doing a dot plot where *both* the size and color (more
specifically, shade of grey) change with the associated value.

I've found examples online for ggplot2 where you can scale the size of the
dot with a value:

http://had.co.nz/ggplot2/graphics/6a053f23cf5bdfe5155ab53d345a5e0b.png

Or scale the color with the value:

http://had.co.nz/ggplot2/graphics/b17bf93530ff6695afb366e65677c17f.png

both of which are from here:
http://had.co.nz/ggplot2/geom_point.html

but I've been playing around with ggplot2 and couldn't figure out how to
do
both at the same time - ideally i want size to increase with a value, and
the shade of grey to get lighter with increasing value.


Any help's appreciated, thanks!

Brian

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Try running this and see if it does what you want. It just uses plain
old plot with the cex arg for size and the col arg for colour...

greyDots <- function() {
  # make up some data
  x <- runif(50, 0, 10)
  y <- runif(50, 0, 10)
  valueMax <- 100
  value <- sample(valueMax, 50)

  # edit these to taste
  maxDotSize <- 5
  maxGreyLevel <- 0.8

  plot(x, y, pch=16, xlim=c(0,10), ylim=c(0,10),
       cex=maxDotSize * value / valueMax,
       col=grey(maxGreyLevel * value / valueMax))
}


On 12 August 2010 13:14, Brian Tsai <btsai00 at gmail.com>
wrote:
> Hi all,
>
> I'm interested in doing a dot plot where *both* the size and color
(more
> specifically, shade of grey) change with the associated value.

On Wed, Aug 11, 2010 at 10:14 PM, Brian Tsai <btsai00 at gmail.com>
wrote:
> Hi all,
>
> I'm interested in doing a dot plot where *both* the size and color
(more
> specifically, shade of grey) change with the associated value.
>
> I've found examples online for ggplot2 where you can scale the size of
the
> dot with a value:
>
> http://had.co.nz/ggplot2/graphics/6a053f23cf5bdfe5155ab53d345a5e0b.png
>
> Or scale the color with the value:
>
> http://had.co.nz/ggplot2/graphics/b17bf93530ff6695afb366e65677c17f.png
>
> both of which are from here:
> http://had.co.nz/ggplot2/geom_point.html
>
> but I've been playing around with ggplot2 and couldn't figure out
how to do
> both at the same time - ideally i want size to increase with a value, and
> the shade of grey to get lighter with increasing value.
qplot(mpg, wt, data = mtcars, colour = qsec, size = qsec) + scale_colour_grey()

Hadley

-- 
Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/