plot seats-votes curves
Plot seats-votes curves produced by seatsVotes
## S3 method for class 'seatsVotes'
plot(x, type = c("seatsVotes", "density"),
legend = "bottomright", transform=FALSE, ...)x |
an object of class |
type |
character, partially matching the options above; see details |
legend |
where to put the legend when plotting with
|
transform |
logical, whether to transform the vote shares for
|
... |
arguments passed to or from other functions (e.g.,
options for the |
A seats-votes curve (with various annotations) is produced
with option type="seatsVotes".
A density plot of the vote shares is
produced with type="density". A bimodal density corresponds to
an electoral system with a proliferation of safe seats for both
parties, and a seats-votes curve that is relatively flat (or
“unresponsive”) in the neighborhood of average district-level
vote shares of 50 percent. The density is fitted using the defaults
in the density function, but with the density constrained
to fall to zero at the extremes of the data, via the from and
to options to density. A rug is added to the
density plot.
If transform=TRUE, the vote shares are transformed prior to
plotting, so as to reduce the extent to which extreme vote shares
close to zero or 1 determine the shape of the density (i.e., this
option is available only for plots of type="density"). The
transformation is a sinusoidal function, a scaled
“log-odds/inverse-log-odds” function mapping from (0,1) to
(0,1): i.e., f(x) = g(kh(x)) where
h(x) is the log-odds transformation h(x) = log[x/(1-x)], k is a scaling parameter
set to sqrt(3), and g(x) is the inverse-log-odds
transformation g(x) =
exp(x)/[1+exp(x)]. Note that this transformation is cosmetic, with
the effect of assigning more of the graphing region to be devoted to
marginal seats.
The function performs the requested plots and exits silently with
invisible{NULL}.
Simon Jackman simon.jackman@sydney.edu.au
data(ca2006)
x <- ca2006$D/(ca2006$D+ca2006$R)
sv <- seatsVotes(x,
desc="Democratic Vote Shares, California 2006 congressional elections")
plot(sv)
plot(sv,type="density")
plot(sv,type="density",transform=TRUE)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.