Survey and Typological-Construction Characterisation of the Rammed Earth Walls of Olías de Oria Castle (Almería) Using Aerial and Terrestrial Photogrammetry

The typological-construction characterisation of earthen wall structures is a prerequisite for proposing any kind of heritage conservation or restoration intervention. This necessarily involves conducting a thorough survey to facilitate the image capture and analysis of the wall surfaces. Photogrammetry offers an affordable and non-invasive solution that guarantees reliable results, as has been proven in a considerable number of projects to date. This paper describes the use of photogrammetry to survey one of the wall sections of Olías de Oria Castle (Almería). A unique aspect of this fortification is its topographical plan, which contains steep gradients outside the walls and therefore necessitated the alternation of aerial and terrestrial photogrammetry. The 3D point cloud obtained permitted the vectorisation of the wall, which in turn provided a reliable graphical base for the development of the typological-construction characterisation that may be used to justify a possible future intervention.