GsTL - The Geostatistics Template Library. GsTL is a C++ library that provides a comprehensive set of tools and algorithms for geostatistics. The algorithms provided include: Kriging : simple kriging (SK) , ordinary kriging (OK) and kriging with trend (KT); Cokriging : simple or ordinary, using either the full cokriging system or one of the Markov models MM1 or MM2; Sequential Simulation : Gaussian simulation, indicator simulation, or multiple-points statistics simulation; P-Field Simulation. Object-based simulation techniques and simulated annealing are currently not covered.