MLE of the Wood bimodal distribution on the sphere: MLE of the Wood bimodal distribution on the sphere
Description
It estimates the parameters of the Wood bimodal distribution.
Usage
wood.mle(y)
Value
A list including:
info
A 5 x 3 matrix containing the 5 parameters, \(\gamma\), \(\delta\), \(\alpha\), \(\beta\) and \(\kappa\) along with their corresponding 95% confidence intervals all expressed in degrees.
modes
The two axis of the modes of the distribution expressed in degrees.
unitvectors
A 3 x 3 matrix with the 3 unit vectors associated with the \(\gamma\) and \(\delta\) parameters.
loglik
The value of the log-likelihood.
Arguments
y
A matrix containing two columns. The first one is the latitude and the second is the longitude, both expressed in degrees.
Author
Michail Tsagris.
R implementation and documentation: Michail Tsagris mtsagris@uoc.gr and Giorgos Athineou <gioathineou@gmail.com>.
Details
The Wood distribution is fitted to some data and its parameters are estimated. It is a bimodal distribution which contains 5 parameters, just like the Kent distribution.
References
Wood A.T.A. (1982). A bimodal distribution on the sphere.
Journal of the Royal Statistical Society, Series C, 31(1): 52--58.