Function for obtaining a sequence of range parameters for the CReSS smoother

getRadiiChoices() has been superseded in favour of getRadiiSequence()

Usage

getRadiiChoices(numberofradii = 10, distMatrix, basis, rvin = NULL)

Arguments

numberofradii: The number of range parameters for SALSA to use when fitting the CReSS smooth. The default is 8. Remember, the more parameters the longer SALSA will take to find a suitable one for each knot location.
distMatrix: Matrix of distances between data locations and knot locations (n x k). May be Euclidean or geodesic distances. Euclidean distances created using makeDists.
basis: character stating whether a 'gaussian' or 'exponential' basis is being used.
rvin: Two parameter vector stating the minimum and maximum range of r for a gaussian basis.

Value

This function returns a vector containing a sequence of range parameters.

Details

The range parameter determines the range of the influence of each knot. Small numbers indicate local influence and large ones, global influence.

References

Scott-Hayward, L.; M. Mackenzie, C.Donovan, C.Walker and E.Ashe. Complex Region Spatial Smoother (CReSS). Journal of computational and Graphical Statistics. 2013. DOI: 10.1080/10618600.2012.762920

Examples


# load data
data(ns.data.re)
# load knot grid data
data(knotgrid.ns)

# make distance matrices for datatoknots and knottoknots
distMats<-makeDists(cbind(ns.data.re$x.pos, ns.data.re$y.pos), na.omit(knotgrid.ns))

# choose sequence of radii
r_seq<-getRadiiChoices(8, distMats$dataDist, basis="gaussian")