Traditional sampling methods are unsuited to spatially autocorrelated data; in geostatistics, autocorrelations are not a problem and sampling is less restrictive. For a detailed description of most geostatistical methods, see E. Isaaks and R. M. Srivastava (1989). A web search for geostatistics software will yield any number of programmes. Before choosing a method, note that, in a user-friendly paper, Kent et al. (2006) PPG 30, 2 warn that it is vital to specify your scale of interest.