The test of new hardware is expensive and time-consuming. Reducing costs is the objective of simulated testing, in which a model might substitute for the actual system under test. Achieving such a degree of fidelity will require validated models not only of the SUT but also of the environment. The IMAPS framework is designed to allow models to interact with databases of the test environment. The validated environmental description uses GIS databases coupled to sophisticated environmental models. This paper discusses the use of GIS as the basis for simulated test environments in the next century.