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

Prof Brian Ripley ripley at stats.ox.ac.uk
Thu Jan 27 10:32:05 CET 2011

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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> and provide commented, minimal, self-contained, reproducible code.

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)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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