Increasing grayscale value in scatter plot with number of points on particular location
On Thu, 27 Jan 2011, Aditya Bhagwat wrote:
Dear Prof. Ripley,
Thanks for your reply.
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.
I am working on Ubuntu Linux. and I tried the suggested approach but got an
empty plot and the following warning message:
In plot.xy(xy, type, ...) :
? semi-transparency is not supported on this device: reported only once per
page
Any suggestions on how to proceed?
Use a device that supports transparency: X11() ought to on a Linux box, pdf() does everywhere.
Many thanks, Aditya 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 -- Aditya Bhagwat
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