orthobasis.poly: Function to compute polynomial of geographical coordinates

In adespatial: Multivariate Multiscale Spatial Analysis

Function to compute polynomial of geographical coordinates

Description

This function computes orthgonal polynomials of geographical coordinates. Polynomials functions are orthogonal and centred for the weights defined in wt (i.e., orthogonal to wt). It is the classical approach to perform trend surface analysis.

Usage

orthobasis.poly(coords, degree = 2, wt = rep(1/nrow(coords), nrow(coords)))

Arguments

coords	either a Spatial* object or a matrix with geographic coordinates
degree	the degree of the polynomial
wt	a vector of weights. It is used to orthogonalize the polynomial functions

Value

an object of class orthobasisSp , subclass orthobasis

Author(s)

Stéphane Dray [e-mail]

References

Dray S., Pélissier R., Couteron P., Fortin M.J., Legendre P., Peres-Neto P.R., Bellier E., Bivand R., Blanchet F.G., De Caceres M., Dufour A.B., Heegaard E., Jombart T., Munoz F., Oksanen J., Thioulouse J., Wagner H.H. (2012). Community ecology in the age of multivariate multiscale spatial analysis. Ecological Monographs 82, 257–275.

See Also

mem orthobasis

Examples

if(require("ade4", quietly = TRUE)){
data(mafragh, package = "ade4")
pol2 <- orthobasis.poly(mafragh$Spatial) 

if(require("adegraphics", quietly = TRUE)){
plot(pol2, mafragh$Spatial)
}
}

adespatial documentation built on Sept. 11, 2024, 7:04 p.m.