An Expect Value for Governing Fuzzy Datum in Environmental GIS

During the exploitation of an archaeological geographical information system, experts need to evaluate the anteriority in pairs of dates which are uncertain and inaccurate, and consequently represented by fuzzy numbers. To build their hypotheses, they need to have an assessment, taking value in [0, 1], of the relation ‘‘lower than’’ between two FNs. We answer the experts’ need of evaluation by constructing an anteriority index based on the Kerre index. Some applications, which constitute a step in the evaluation of the evolution of Reims during the domination of the Roman Empire, illustrate the use of the anteriority index.