plot.OCcoords: Optimal Classification Coordinate Plot

Description

plot.coords reads an Optimal Classification object in 2 user-specified dimensions and plots the coordinates of each member, applying separate colors and shapes to each party by default. A unit circle is included to emphasize the constraints on the Optimal Classification coordinates, and options to select non-party attributes of legislators are included. For a 1D OCobject object, Optimal Classification ranks are plotted against themselves, so they appear on a straight line.

Usage

# S3 method for OCcoords
plot(x, main.title="OC Coordinates",
    d1.title="First Dimension", d2.title="Second Dimension", dims=c(1,2),
    plotBy="party", color=TRUE, shape=TRUE, cutline=NULL, Legend=TRUE,
    legend.x=0.8, legend.y=1,...)

Value

A coordinate plot.

Arguments

x: an OCobject output object.
main.title: string, coordinate plot title.
d1.title: string, x-axis label.
d2.title: string, y-axis label.
dims: vector of length 2, specifying the dimensions to be plotted.
plotBy: string, name of a variable in OCobject\$legislators. plot.coords will plot coordinates using this variable as a selector.
color: logical, marks different groups specified by plotBy using different colors if TRUE.
shape: logical, marks different groups specified by plotBy using different shapes if TRUE.
cutline: vector, selects roll calls by row number for which a cutting line is desired.
Legend: logical, include a generic legend.
legend.x: numeric, corresponds to the 'x' argument of legend().
legend.y: numeric, corresponds to the 'y' argument of legend().
...: other arguments to symbols.

Author

Keith Poole ktpoole@uga.edu

Jeffrey Lewis jblewis@ucla.edu

James Lo lojames@usc.edu

Royce Carroll rcarroll@rice.edu

Examples

Run this code

    #This data file is the same as that obtained using:
    if (FALSE) {
    data(sen90)
    sen90oc <- oc(sen90,dims=2,polarity=c(7,2)) 
	}

    data(sen90oc)
    summary(sen90oc)
    plot.OCcoords(sen90oc)