Gstat

Gstat is a program for the modelling, prediction and simulation of geosta- tistical data in one, two or three dimensions. Geostatistical data are data (measurements) collected at known locations in space, from a function (pro- cess) that has a value at every location in a certain (1, 2 or 3-D) domain. These data (or some transform of them) are modelled as the sum of a con- stant or varying trend and a spatially correlated residual. Given a model for the trend, and under some stationarity assumptions, geostatistical modelling involves the estimation of the spatial correlation. Geostatistical prediction (‘kriging’) is finding the best linear unbiased prediction (the expected value) with its prediction error for a variable at a location, given observations and a model for their spatial variation. Simulation of a spatial variable is the creation of randomly drawn realizations of a field given a model for the data, possibly conditioned on observations.