A discussion on the quantification and classification of geodiversity indices based on GIS methodological tests

Abstract

Quantitative assessment methods are attaining special attention in geodiversity research. Procedures to map geodiversity indices have been proposed by several authors though there is no consensus on how to best apply and replicate them in diverse areas. A contribution to the quantitative mapping of geodiversity using GIS tools of quantification and classification is presented. These procedures were applied in the municipality of Miguel Pereira, Rio de Janeiro, Brazil. A quantification stage is supported by the multiparts technique, in which the geodiversity elements are considered without pondering their repetition, and by the singleparts technique, where the repetitions are counted. Geodiversity is then mapped and classified according to the MOV (maximum obtained value) that considers the highest score obtained by the sum of the geodiversity sub-indices and to the MPV (maximum possible value) defined by the sum of the maximum scores in each of the geodiversity sub-indices. The maps produced according to the singleparts tools reflect a higher difference between the minimum and maximum scores of geodiversity, and using the MPV more areas are classified with low geodiversity. Fieldwork surveys support the idea that combining the multiparts technique for geodiversity quantification with the MOV to its classification is more appropriate to characterize the geodiversity of the area. Nevertheless, using different methodological approaches may generate significantly different results, what must be taken into account when considering geodiversity as a support tool in land management.