metria: digital photogrammetry for architecture, heritage, engineering and industry

The Oviedo Cathedral is without any doubt the most important asturian gothic work. One of the most important aspects of the Oviedo Cathedral for the Spanish gothic history is the fact that on its walls there are architectural elements representing all the gothic architecture phases, from the classicism at the end of the XIII century, to the late Hispano-Flemish period in the XVI century, going through the intermediates in the XIV century (mannerist) or in the XV century (flamboyant). After a very large construction period, this cathedral is an edifice mainly built in the XV century with a conservative style, structured in three naves and side chapels, large transept and tripartite sanctuary.

The objective of our work was the photogrammetric survey of the four tower facades to obtain plans to a 1:50 scale using the appropriate representation precission with 0.2 mm lines, according to the ISO normative that correspond to a 1 cm restitution precission. The rough tower facades dimensions are 12×73 meters.

West and South facades of the Oviedo Cathedral. Consejería de Cultura, Comunicación Social y Turismo. Principality of Asturias.
Clic on the image to zoom.

Given the great height of the tower and the adjacent streets narrowness, the photographs takings were carried out from a crane and from the adjacent buildings. To make the task easier, the tower was subdivided in five zones distributed according to the height, treating each one of them as an independent project at the beginning; once the consistency of each single project assured we proceed with the unification of them all, using the overlapping zones planned with this purpose. In order to finally assure the global project consistency we used classic topography as support.

The delineation work to obtain the final plans was very demanding, with the aim of suitably representing all the visible interest elements to the representation scale; the line types was extremely carefully chosen, obtaining thus the maximum definition level that can be provided using this scale. The final precision in the survey made possible the tower spire movement detection, of centimeter order, due to the tower ashlar expansion throughout the day.