Circle packing in R (again)

April 29, 2015
By

(This article was first published on Last Resort Software, and kindly contributed to R-bloggers)

Back in 2010 I posted some R code for circle packing. Now, just five years later, I’ve ported the code to Rcpp and created a little package which you can find at GitHub.

The main function is circleLayout which takes a set of overlapping circles and tries to find a non-overlapping arrangement for them. Here’s an example:

And here’s the code:


# Create some random circles, positioned within the central portion
# of a bounding square, with smaller circles being more common than
# larger ones.

ncircles <- 200
limits <- c(-50, 50)
inset <- diff(limits) / 3
rmax <- 20

xyr <- data.frame(
x = runif(ncircles, min(limits) + inset, max(limits) - inset),
y = runif(ncircles, min(limits) + inset, max(limits) - inset),
r = rbeta(ncircles, 1, 10) * rmax)

# Next, we use the `circleLayout` function to try to find a non-overlapping
# arrangement, allowing the circles to occupy any part of the bounding square.
# The returned value is a list with elements for the layout and the number
# of iterations performed.

library(packcircles)

res <- circleLayout(xyr, limits, limits, maxiter = 1000)
cat(res$niter, "iterations performed")

# Now draw the before and after layouts with ggplot

library(ggplot2)
library(gridExtra)

## plot data for the `before` layout
dat.before <- circlePlotData(xyr)

## plot dta for the `after` layout returned by circleLayout
dat.after <- circlePlotData(res$layout)

doPlot <- function(dat, title)
ggplot(dat) +
geom_polygon(aes(x, y, group=id), colour="brown", fill="burlywood", alpha=0.3) +
coord_equal(xlim=limits, ylim=limits) +
theme_bw() +
theme(axis.text=element_blank(),
axis.ticks=element_blank(),
axis.title=element_blank()) +
labs(title=title)

grid.arrange(
doPlot(dat.before, "before"),
doPlot(dat.after, "after"),
nrow=1)

To leave a comment for the author, please follow the link and comment on their blog: Last Resort Software.

R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: Data science, Big Data, R jobs, visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web Scraping) statistics (regression, PCA, time series, trading) and more...



If you got this far, why not subscribe for updates from the site? Choose your flavor: e-mail, twitter, RSS, or facebook...

Comments are closed.

Sponsors

Never miss an update!
Subscribe to R-bloggers to receive
e-mails with the latest R posts.
(You will not see this message again.)

Click here to close (This popup will not appear again)