Spatial Representation and Reasoning About Fold Strata: A Qualitative Approach

This paper proposes the method that handles strata based on qualitative spatial reasoning. We make a model for typical fold structure projected onto a two-dimensional plane, extracted by a rectangle. We give a symbolic representation to the model with the features of qualitative configuration and qualitative shape, and propose a reasoning method on this representation. First, we define the validity required of the representation and show the correspondence between the model and its representation. Next, we define operations such as rotation and symmetric transitions on the representation and show that they preserve the validity. Finally, we define the rules of connecting the models, and show reasoning on construction of global data by applying them. When multiple local data collected in distant locations are given, we can find global data by inserting missing parts. The approach based on qualitative spatial reasoning provides a logical explanation of the processes involved in strata-generation prediction, which in the field of structural geology have been examined manually to date, and enables to find results that manual analysis may overlook.