Considered methods
closest observation method
\(\hat{Z}(s_0) = Z(s_{closest})\)
inverse distance weighting method (IDW)
\(\hat{Z}(s_0) = \sum_{i = 1}^{n}(Z(s_i) \cdot w_i)\)
- with \(w_i = d_i^{-\beta} / \sum_{i = 1}^{n}d_i^{-\beta}\)
- optionally replace \(n\) by \(k < n\): use only the \(k\) nearest locations
nearest neighbours method:
- special case of IDW with \(\beta = 0\) and \(k < n\) so that \(w_i = 1 / k\)