Inverse of Lambert's equal area projection {Directional} | R Documentation |
Inverse of Lambert's equal area projection
Description
It takes some points from the cartesian coordinates and maps them onto the sphere. The inverse os the Lambert's equal area projection.
Usage
lambert.inv(z, mu)
Arguments
z |
A two- column matrix containing the Lambert's equal rea projected data. |
mu |
The mean direction of the data on the sphere. |
Details
The data are first mapped on the sphere with mean direction equal to the north pole. Then, they are rotated to have the given mean direction. It is the inverse of the Lambert's equal are projection.
Value
A matrix containing spherical data (unit vectors).
Author(s)
Michail Tsagris.
R implementation and documentation: Michail Tsagris mtsagris@uoc.gr and Giorgos Athineou <gioathineou@gmail.com>.
References
Kent, John T. (1982). The Fisher-Bingham distribution on the sphere. Journal of the Royal Statistical Society. Series B (Methodological) 44(1):71–80.
See Also
Examples
m <- rnorm(3)
m <- m / sqrt( sum(m^2) )
x <- rvmf(20, m, 19)
mu <- vmf.mle(x)$mu
y <- lambert( euclid.inv(x) )
lambert.inv(y, mu)
euclid.inv(x)