make.M {DSSP}

Precision Matrix Function

Description

This function creates the precision matrix for the spatial prior based on thin-plate splines and returns the matrix M, and its eigenvalues and eigenvectors

Usage

make.M(X, covariates)

Arguments

X

a matrix of spatial coordinates. It is recommended that the coordinates be scaled and centred.

covariates

the observed values for the covariates (including intercept).

Details

The M matrix is the precision matrix for the spatial effects from the direct sampling spatial prior (DSSP) model. M is based on thin plate splines basis functions, see White et. al. 2019 for more details on how the matrix M is constructed.

Value

A list containing the precision matrix M and the object M.eigen containing eigenvalues and eigenvectors for the matrix M.

Examples

## Use the Meuse River dataset from the package 'gstat'

library(sp)
library(gstat)
data(meuse.all)
coordinates(meuse.all) <- ~ x + y
X <- scale(coordinates(meuse.all))
make.M(X)