Reliability map: a quantitative method for analyzing the degree of reliability of digital reconstructions of demolished or heavily modified historical heritage sites

Abstract

The present work proposes a “reliability map”: a quantitative method that aims to inform the degree of reliability of the virtual reconstruction of a scenario of the past, whose reconstruction started mainly from photographs and maps from previous times. The proposed method is divided into two parts. The first refers to the production flow of the 3D scenario, which includes the collection of iconographic data and the crossing of old maps and photos, with a view to the three-dimensional modeling of the environment. The second concerns the use of an algorithm (produced in the software @Rhino / plugin Grasshopper), which, through the information in the photographs, performs the calculations whose result is a heat map that informs which are the areas that have greater or lower degree of reliability in relation to the researcher's archtectonic and urbanistic hypotheses about what the reconstructed site. Finally, as a way to demonstrate the quantitative methodology, the algorithm was applied in two virtual reconstructions that portray different times in the same place. Largo de Nazaré, located in the city of Belém, was chosen as a case study. The comparison of the results between both periods showed that despite being the same area and the same virtual reconstitution techniques, the maps helped to clarify where each digital model required a greater or lesser degree of deduction, therefore, it proved to be useful to assist readers about which parts are more or less reliable in relation to the records of the past.