Report statistics of ADP or ADV velocities, such as means and variance ellipses.

velocityStatistics(x, control, ...)

Arguments

x

an adp or adv object.

control

An optional list used to specify more information. This is presently ignored for adv objects. For adp objects, if control$bin is an integer, it is taken as the bin to be selected (otherwise, an average across bins is used).

...

additional arguments that are used in the call to mean().

Value

A list containing items the major and minor axes of the covariance ellipse (ellipseMajor and ellipseMinor), the angle of the major axis anticlockwise of the horizontal axis (ellipseAngle), and the x and y components of the mean velocity (uMean and vMean).

See also

Examples

library(oce) data(adp) a <- velocityStatistics(adp) print(a)
#> $ellipseMajor #> [1] 0.6442399 #> #> $ellipseMinor #> [1] 0.04197328 #> #> $ellipseAngle #> [1] 57.09922 #> #> $uMean #> [1] 0.095503 #> #> $vMean #> [1] 0.1760109 #>
t <- seq(0, 2*pi, length.out=100) theta <- a$ellipseAngle * pi / 180 y <- a$ellipseMajor * cos(t) * sin(theta) + a$ellipseMinor * sin(t) * cos(theta) x <- a$ellipseMajor * cos(t) * cos(theta) - a$ellipseMinor * sin(t) * sin(theta) plot(adp, which="uv+ellipse+arrow")
lines(x, y, col='blue', lty="dashed", lwd=5)
arrows(0, 0, a$uMean, a$vMean, lwd=5, length=1/10, col='blue', lty="dashed")