Each node represents an R package; the size is how often it was run.
The size of its pie slice is how often it was run with this app (plyr
A link between nodes shows that these
packages happened to be loaded at the same time by some script by some user.
Solid lines indicate static dependencies (i.e. those enforced
by R's package loading mechanism). Dotted lines are packages users chose
to use during the same R session.