ABSTRACT
The dry stone construction technique is the oldest method used by humanity. Moreover, it is the type used most frequently worldwide. In the Iberian Peninsula, this technique was used regularly between from the end of the eighteenth century and the beginning of the twentieth century. Because of the mechanization of fieldwork and the lack of generational relief, dry stone heritage constructions are in severe danger. Currently, it is impossible to conserve all the constructions. Though it might seem unimportant, new surveying technologies make it possible to register these structures with unprecedented accuracy. Thus, they may be catalogued before they are ruined.
Digital photogrammetry and terrestrial laser scanning are two massive data capture techniques. Both are commonly used in architectural heritage surveys. These safe, contactless, and non-invasive procedures allow registration of millions of topographical points quickly, and with great accuracy. In the case of dry stone vernacular heritage, photogrammetry offers great advantages, as the surfaces of these constructions have very marked textures. Additionally, these constructions are often built in irregular locations that are difficult to access. This causes difficulties in the use of heavy equipment.
Despite its positive features, the appearance of smaller and lighter laser devices leads us to reconsider photogrammetry’s use in the field. This article presents a comparative analysis between digital photogrammetry (using the Structure from Motion (SfM) technique) and a recently released laser scanner in performing a 3D topographical survey of dry stone constructions.
