spweights: Compute weights from distance matrix
In rcarbon: Calibration and Analysis of Radiocarbon Dates

Description Usage Arguments Details Value Examples

Function for computing a matrix of gaussian or fixed weights from distance matrix

1	spweights(distmat, h = NULL, kernel = "gaussian")

`distmat`	a symmetric matrix of inter-site distances (in km).
`h`	parameter of the Gaussian distance decay function.
`kernel`	indicates the type of weighting function, either 'fixed' or 'gaussian'. Default is 'gaussian'.

This function generates a weight matrix (required for the SPpermTest) function. When kernel=="fixed", the weight w_{ij} between site i and j is equal to 1 when their interdistance d_{ij} is below h, and equal to 0 when d_{ij}>h.When kernel=="gaussian", the weight is calculated with formula exp(-d_ij^2/h^2).

An object of class spatialweights

lon <- c(11.3426,0.1278,0.1218)
lat <- c(44.4949,51.5074,52.2053)
library(sp)
d <- spDists(x=cbind(lon,lat),y=cbind(lon,lat))
spweights(d,h=100)
spweights(d,h=100,kernel="fixed")