shotGroups (version 0.2-2)

drawEllipse: Draw a single ellipse

Description

Adds a single ellipse to an already opened plot.

Usage

drawEllipse(ctr, shape, radius, nv = 100, fg = par('fg'),
            bg = NA, colCtr = NA, lty = par('lty'),
            lwd = par('lwd'), pch = par('pch'), cex = par('cex'))

Arguments

ctr

a numerical 2-vector giving the (x,y)-coordinates of the center.

shape

a numerical symmetric (2 x 2)-matrix whose eigen-structure determines the ellipse's shape.

radius

a numerical value giving the ellipse's magnification factor.

nv

number of vertices in the approximating polygon.

fg

color of the ellipse's rim.

bg

the ellipse's fill color. Set to NA for a fully transparent ellipse.

colCtr

color of the center point. Set to NA to omit.

lty

line type of the ellipse.

lwd

line width of the ellipse.

pch

symbol used for the center of the ellipse.

cex

magnification factor for the symbol used for the center of the ellipse.

Details

This function is mainly a wrapper for polygon.

See Also

polygon

Examples

## error ellipse for a set of points
xy     <- matrix(round(rnorm(100, 0, 8), 2), ncol=2)
ctr    <- colMeans(xy)
covMat <- cov(xy)
plot(xy, pch=16, asp=1)
drawEllipse(ctr, covMat, radius=1, fg='blue', colCtr='blue',
            lwd=2, pch=4, cex=2)