Through interacting with urban and architectural spaces, pedestrian pathway's ambient fingerprints delineate ambiences with identifiable characteristics, thus characterizing landscape perception potentialities. Based on a measure of the surrounding open spaces using isovists, our proposal consists in building a sensory Digital Terrain models (DTM) in which the entropy of the function of radial distances is used as a third dimension. As a case study, the distribution of entropy of the Place Royale square in Nantes (France), presented in a dedicated DTM, helps us characterizing the space " intimacy quality " for each observation point. This measure constitutes a relevant indicator of spatial wealth, revealing several perspectives occurrences for a given point of view during an urban walk. This way, this geotopical process establishes a spatial potential, so as to provide to a pedestrian the ability to reach specified townscapes to be contemplated. This sensorial investigation aims to constitute a tool basis for multi-sensorial planning and design process.