Who sees the sea? Sea-view potential by façade and floor from cadastral LoD1 models on the Costa del Sol

Working paper, version r120 of 10 November 2026. Views are among the most valued and least measured attributes of a home. We present an open-data method that estimates the sea-view potential of every free façade of every residential building at three floors (ground, middle and top; other floors take the nearest of them), from cadastral footprints with floor counts and a national terrain model. Run for 158,060 buildings of 21 municipalities on Spain's Costa del Sol in under an hour on two cores, it finds that 52 % of buildings see some sea from their top floor and 36 % have an open view (20° or more). Traced over a LiDAR surface in a pilot, scores agree with the model's inside cadastral footprints (96.7 % of viewpoints in the same class at 20°), but structures the cadastre does not record lower the sea seen from the top floor by 6.1–9.0° on average. Against the photographs of 93 homes for sale, labelled blind by AI models of two developers with ties decided by the author, the score has an AUC of 0.80 (95 % CI 0.70–0.89; 0.81 against the first-round labels); at 20° it is sensitive (0.90) but not specific (0.45). Dwelling figures depend on how dwellings are allocated to façades and floors: 42 % of dwellings are on a floor with open-view potential under the main rule, and 12–45 % across the allocation, geometry and vegetation scenarios tested. As an application, higher-income census sections tend to have more modelled view potential within municipalities, with uncertain size and fragile inference (about two effective clusters); on terrain alone the difference largely disappears. Code and façade-level data reproduce the main results. The article, with its figures and how to cite it: https://casas.es/en/research/who-sees-the-sea Data and code: https://doi.org/10.5281/zenodo.24106387 The Costa del Sol on CASAS.ES: https://casas.es/malaga/costa-del-sol-comarca/ How CASAS.ES computes its figures: https://casas.es/en/methodology