lambert.inv: Inverse of Lambert's equal area projection

In Directional: A Collection of Functions for Directional Data Analysis

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 [e-mail] and Giorgos Athineou <[e-mail]>.

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

lambert

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)

Directional documentation built on Oct. 30, 2024, 9:15 a.m.