[R] Scatterplot Showing All Points

Jari Oksanen jari.oksanen at oulu.fi
Tue Dec 18 09:22:36 CET 2007

Wayne Aldo Gavioli <wgavioli <at> fas.harvard.edu> writes:

> Hello all,
> I'm trying to graph a scatterplot of a large (5,000 x,y coordinates) of data
> with the caveat that many of the data points overlap with each other (share the
> same x AND y coordinates).  In using the usual "plot" command,
> > plot(education, xlab="etc", ylab="etc")
> it seems that the overlap of points is not shown in the graph.  Namely, there
> are 5,000 points that should be plotted, as I mentioned above, but because so
> many of the points overlap with each other exactly, only about 50-60 points are
> actually plotted on the graph.  Thus, there's no indication that Point A shares
> its coordinates with 200 other pieces of data and thus is very common while
> Point B doesn't share its coordinates with any other pieces of data and thus
> isn't common at all.  Is there anyway to indicate the frequency of such points
> on such a graph?  Should I be using a different command than "plot"?
One suggestion seems to be still missing: 'sunflowerplot' of base R. May look
taggy, though, if you have 200 "petals". 

Actually the documentation of sunflowerplot is wrong in botanical sense.
Sunflowers have composite flowers in capitula, and the things called 'petals' in
documentation are ligulate, sterile ray-florets (each with vestigial petals
which are not easily visible in sunflower, but in some other species you may see
three (occasionally two) teeth). 

cheers, jari oksanen

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