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