Shape-based Modelling: an Application to the Recostruction of Antartic Sea Floor

Shape-based modelling is a general approach to surface representation, which has a great importance in the specific context of sea floors reconstruction, especially in areas where measurements can involve critical operations, such as in Antarctica. The shape based reconstruction is achieved performing a geometric reasoning tn the raw data to delineate, whenever possible, a shape stnicture on which the surface reconstruction can be based. An example of the proposed approach is presented for die reconstruction of the Antarctic sea floor. Data are collected by surveys carried out along parallel courses during which the depth of the sea is measured at almost regular intervals. The sea floor is then represented by a set of profiles, corresponding to vertical cross sections. The surface reconstruction is performed in three steps. First, a shape-based generalisation is carried out on the profiles using a combined method based on wavelet theory and (n the classical Douglas and Peucker algorithm. The next step consists of finding similarities in the morphology of adjacent profiles, which may suggest the presence of surface features, such as ridges and ravines. Finally, the deduced surface features are used to build a kind of skeleton on which the most appropriate triangulation can be constructed.