Contour plot (on the plane) of the ESAG and Kent distributions without any data {Directional}

Contour plot (on the plane) of the ESAG and Kent and ESAG distributions without any data

Description

The contour plot (on the plane) of the spherical ESAG and Kent distributions is produced.

Usage

esag.contour(mu, gam, lat, long)
kent.contour(k, b)

Arguments

k

The concentration parameter.

b

The ovalness parameter. It has to be less than k/2 in order for the distribution to be unimodal. Otherwise it is bimodal.

mu

The mean vector the ESAG distribution, a vector in R^3.

gam

The two gamma parameters of the ESAG distribution.

lat

A positive number determing the range of degrees to move left and right from the latitude center. See the example to better understand this argument.

long

A positive number determing the range of degrees to move up and down from the longitude center. See the example to better understand this argument.

Details

The goal of this function is for the user to see how the Kent or the SAG distribution looks like.

Value

A plot containing the contours of the distribution.

Author(s)

Michail Tsagris and Christos Adam.

R implementation and documentation: Michail Tsagris [e-mail] and Christos Adam [e-mail].

References

Kent John (1982). The Fisher-Bingham distribution on the sphere. Journal of the Royal Statistical Society, Series B, 44(1): 71–80.

Paine P.J., Preston S.P., Tsagris M. and Wood A.T.A. (2018). An Elliptically Symmetric Angular Gaussian Distribution. Statistics and Computing, 28(3):689–697.

See Also

vmf.contour, vmf.kerncontour, spher.esag.contour

Examples

kent.contour(10, 4)

mu <- colMeans( as.matrix( iris[,1:3] ) )
gam <- c(1,0.5)
esag.contour(mu, gam, 50, 50)
esag.contour(mu, gam, 30, 40)