ABSTRACT
Climate or environmental data are often presented in the form of a map, for example the maximum temperatures on a given day in a country, the concentrations of some pollutant in a city or the mineral content in soil. In mathematical terms, such maps can be described as realisations from a random field, that is, an ensemble of random quantities indexed by points in a region of interest. Samples from a Gaussian random field may be obtained using the package RandomFields: Simulation and analysis of random fields. The data include topsoil heavy metal concentrations for 155 locations in a flood plain of the Meuse river in the southern-most province of the Netherlands close to the village of Stein. The assumption of a constant mean inherent in the ordinary kriging framework does not seem realistic. In particular, zinc concentrations seem to be correlated with the distance to the river bed.
