[R] Increasing grayscale value in scatter plot with number of points on particular location

[Prof Brian Ripley]

This is one of the main points of supporting semi-transparent colours.
You haven't told us your platform or graphics device (see the posting 
guide), but plotting with something like col=rgb(0,0,0,0.2) may work.

On Thu, 27 Jan 2011, Aditya Bhagwat wrote:

> Dear all,
>
> When making a plot with the command plot(xVector, yVector), there are many
> points that collide on the same place in the plot. In order to make this
> plot clearer, I have been looking for a way to colour the points based on
> the number of points that fall onto each other. If only one point falls on a
> particular location, make it gray, if many points fall, make it black.
>
> I tried to search the help archives, but didn't find any useful answers.
> Anyone has any suggestion?
>
> Many thanks for your help!
>
> Aditya
>
> -- 
> Aditya Bhagwat
>
> 	[[alternative HTML version deleted]]
>
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>

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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