Digitalización de cuevas con arte paleolítico parietal de Bizkaia. Análisis científico y divulgación mediante nuevas técnicas de visualización

We present  three  case  studies  illustrating  the  virtual  reproduction  of  caves  that  belong  to  the  most  important  artistic ensemble of the Paleolithic from Bizkaia (Spain): Benta Laperra, Askondo and Lumentxa. The complex morphology of the cavities, the fineness of their engravings and the poor definition of their paintings imply technical difficulties to achieve faithful reproduction of their geometry and appearance. The methodology applied in these caves, based on a combination of photogrammetric and surveying techniques, allows the creation of a complete virtual replica, without shadow zones and a detailed reproduction of their engravings and paintings. At the same time, this replica has given rise to a type of technical documentation that very faithfully and objectively facilitates the analysis and interpretation of the cave. On the one hand, series  of  longitudinal  and  transverse  sections  have  been  generated, extracting  information  of  the  cut  profile  and  the projection of the surfaces through orthoimages of elevation-section with a level of resolution of 2 mm per pixel, equivalent to a scale of representation 1/10. In addition, the georeferencing of the caves has allowed the research team to generate cartography of elevations of floor and ceiling by means of contour lines and to overlap the cartography of the National Geographic Institute (IGN) to measure the distance that separates the ceiling of the cave from the external surface. It can be used to detect critical points that must be taken into account in case of possible actions in forestry or infrastructure projects. Finally, these virtual replicas allow the dissemination of a wealth in detail, through new interactive methods of visualization and virtual reality. In conclusion, the presented methodology means an advance with respect to the existing techniques thus providing solutions for both technical and informative applications