Edzer J. Pebesma
Gstat: Multivariable Geostatistics for S
****************************************

This paper introduces the \texttt{gstat} package for the S language (R,
S-PLUS). The package provides multivariable geostatistical modelling,
prediction and simulation, as well as several visualisation functions.
Gstat (http://www.gstat.org) was started 10 years ago and was released
under the GPL in 1996; it is closely linked to several GIS systems. It
was not initially written for teaching purposes, but for research
purposes, emphasizing flexibility, scalability and portability. It can
deal with a large number of practical issues in geostatistics, including
change of support (block kriging), simple/ordinary/universal (co)kriging,
fast local neighbourhood selection, flexible trend modelling, variables
with different sampling configurations, and efficient simulation of large
spatially correlated random fields, indicator kriging and simulation, and
(directional) variogram and cross variogram modelling. The formula/models
interface is used to define multivariable geostatistical models. This paper
presents the functionality provided by the \texttt{gstat} S package,
discusses a number of design and implementation issues, and advantages
and shortcomings of the S environment for multivariable geostatistics.