This chapter presents innovative approaches to visibility analysis. Recent advances in Geographical Information System (GIS) and 3D technologies allow us to assess the visual impact of features, either in the landscape or in architectural space, by employing a fully 3D method performed in a georeferenced space in which different simulation scenarios can be created based on critical-source evaluation and a transparent approach to the virtual reconstruction of ancient space. Indeed, one of the main advances is that today visibility analysis can be performed in a full-3D environment, where GIS-based analytical tools are employed. Line-of-Sight (LOS) analysis is presented as a means to explore the visual qualities of inscriptions and wall paintings in a Pompeian house and, on a more general level, to define new workflows for investigating the spatial configuration of virtually reconstructed historical spaces. Additionally, other case studies are discussed in an attempt to generate new insights into the applicability of LOS analysis in very diverse research contexts. A range of archaeological foci, from medieval churches to prehistoric settlements, can now be re-examined by taking into account a human-centred form of investigation.