| lsfit.circle {circular} | R Documentation |
Fit a 2D circle to an (x,y) dataset using LS.
lsfit.circle(x, y, init = NULL, units = c("radians", "degrees"),
template = c("none", "geographics"),
modulo = c("asis", "2pi", "pi"), zero = 0, rotation = c("counter", "clock"), ...)
## S3 method for class 'lsfit.circle':
print(x, digits = max(3, getOption("digits") - 3), ...)
x |
either a matrix with two columns or a vector. |
y |
if x is a vector then y must be a vector with the same length. |
init |
initial values of the parameters. A vector of length 3 with
the following components: radius of the circle, x-coordinate of the
center, y-coordinate of the center. If NULL the vector is set
to c(max(c(abs(x-mean(x)), abs(y-mean(y)))), mean(x), mean(y). |
units |
the units used in defining the angles between
observations and the center of the circle. See circular. |
template |
the template used in defining the angles between
observations and the center of the circle. See circular. |
modulo |
the modulo used in defining the angles between
observations and the center of the circle. See circular. |
zero |
the zero used in defining the angles between
observations and the center of the circle. See circular. |
rotation |
the rotation used in defining the angles between
observations and the center of the circle. See circular. |
... |
further parameters passed to the optim function. |
digits |
the number of digits to be printed. |
lsfit.circle uses the optim function to minimize the sum of the
squared residuals between the observations and the optimally fitting circle.
An object of class lsfit.circle.
coefficients |
a vector of length 3 with the estimated radius and coordinate of the center of the fitted circle. |
x |
the x-coordinate. |
y |
the y-coordinate. |
x.centered |
the x-coordinate re-centered at the center of the circle. |
y.centered |
the y-coordinate re-centered at the center of the circle. |
angles |
angles of the observations with respect to the center
coordinate of class \circular. |
radius |
the distance between the observations and the center coordinate |
convergence |
value from the function optim. |
optim |
the output from the function optim. |
call |
match.call(). |
Claudio Agostinelli and Ulric Lund
Coope, I. (1993). Circle fitting by linear and non-linear least squares. Journal of Optimization Theory and Applications, 76, 381-388.
data(coope) res <- lsfit.circle(x=x.coope, y=y.coope) res plot(res) par(mfcol=c(1,2)) plot(res$angles) hist(res$radius) plot(circular(0), type="n", xlim=c(-5.2, 5.2), ylim=c(-5.2, 5.2), xlab="The Radius of the circle \n is measured from the base line of the axes.") lines(x=res$angles, y=res$radius, join=TRUE, type="b") ff <- function(x) sqrt((res$coefficients[1]*cos(x))^2+(res$coefficients[1]*sin(x))^2) curve.circular(ff, add=TRUE, join=TRUE, nosort=FALSE, col=2) windrose(x=res$angles, y=res$radius)