st_coordinates()
sf
inla()
\[\hat{Z}(s_0) = \sum_{i = 1}^{k}(Z(s_i) \cdot w_i)\]
\[w_i = d_i^{0} / \sum_{i = 1}^{k}d_i^{0} = 1 / k\]
nn <- gstat( formula = vble ~ 1, data = d2, locations = ~ x + y, nmax = 5, set = list(idp = 0) )