Fuzzy relational calculus in land evaluation

In recent years, methods of fuzzy reasoning were developed for situations akin to those found in land evaluation, in which a decision about land suitability must often be based upon imprecise information. The accuracy of such land evaluations depends on the quality of weighing land qualities with respect to their effect on crop production. The advantage of the fuzzy set approach is that class boundaries are not sharply defined, thus allowing the possibility of partial membership to a class. However, the application of fuzzy set theory in land evaluation is often limited to the use of membership functions and has weaknesses with regard to the way weights are attributed to the land qualities considered. Fuzzy relational calculus is introduced to overcome these problems. This new approach is based on fuzzy relations between land qualities and land units. Such a relation mathematically describes the suitability for a particular crop. Relational calculus offers the possibility to construct new relations from those defined previously. It allows to introduce weight coefficients that account for the importance of each land quality considered.