R help - Jan 2011 - Increasing grayscale value in scatter plot with number of points on particular location

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]]

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]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> 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