ellipse {IsoplotR} | R Documentation |
Get error ellipse coordinates for plotting
Description
Constructs an error ellipse at a given confidence level from its centre and covariance matrix
Usage
ellipse(x, y, covmat, alpha = 0.05, n = 50)
Arguments
x |
x-coordinate (scalar) for the centre of the ellipse |
y |
y-coordinate (scalar) for the centre of the ellipse |
covmat |
the [ |
alpha |
the probability cutoff for the error ellipses |
n |
the resolution (number of segments) of the error ellipses |
Value
an [nx2
] matrix of plot coordinates
Examples
x = 99; y = 101;
covmat <- matrix(c(1,0.9,0.9,1),nrow=2)
ell <- ellipse(x,y,covmat)
plot(c(90,110),c(90,110),type='l')
polygon(ell,col=rgb(0,1,0,0.5))
points(x,y,pch=21,bg='black')
[Package IsoplotR version 6.2 Index]