HERITAGE SURVEY AND SCIENTIFIC ANALYSIS OF THE WATCHTOWERS THAT DEFENDED THE LAST ISLAMIC KINGDOM IN THE IBERIAN PENINSULA (THIRTEEN TO FIFETEENTH CENTURY) L. J. García-Pulido a , J. Ruiz Jaramillo a , Mª. I. Alba Dorado a a Dept. of Art and Architecture. High School of Architecture of the University of Malaga, The International Campus of Excellence Andalucía TECH, Spain luis.garcia@uma.es, jonaruizjara@uma.es, maribelalba@uma.es KEY WORDS: New technologies applied to the Heritage documentation, Medieval military architecture, Dissemination and restoration, The Islamic Nasrid Kingdom of Granada, Watchtowers and defensive towers. ABSTRACT: The Islamic Nasrid kingdom of Granada occupied the mountainous areas of the southeastern area of the Iberian Peninsula. There, a natural border was established between the Nasrid kingdom and the Christian kingdom of Castile from 1232 to 1492. To control this frontier and establish visual communication between it and the Nasrid center at the Alhambra citadel, an extensive network of watchtowers and defensive towers was constructed. Studies have been done of individual towers, but no comparative study has been undertaken of all of them. Graphic, homogenous, and exhaustively planimetric documentation would bring together existing information on the majority of them and enable comparative analysis. For this reason, this work conducts systematic architectural surveys of all these military structures, using photogrammetry. In addition to studying the construction typology and techniques, the structural capacity of these towers has been analyzed. It examines how they have been affected by human and natural destructive forces, especially earthquakes, which are common in eastern Andalusia. Although all the historical military architecture is protected by the Spanish and Andalusian Heritage laws, many of these medieval towers and their cultural landscapes are in severe risk. The towers are being studied as individual specimens (emphasizing their differences) and as a unit in a typological group (looking for similarities and unifying characteristics). New technologies for Information and Communication are being used in order to disseminate the results among specialists and to make them available to the general public. Guidelines for restoration projects are also being formulated from the cases analyzed. 1. INTRODUCTION Given their historical condition as a frontier of kingdoms and civilizations —Islamic and Christian in medieval Iberia— these towers are located in unique sites; being erected as reference landmarks of the territories on which they stand. These fortifications, with very diverse typology and morphology, are a faithful testimony to the different territorial structure that has taken place throughout history (Acién Almansa, 1995; Argüelles Márquez, 1995; Arié, 1992; Malpica Cuello, 1996; Tembory Álvarez, 1985; Terrasse, 1954). That means that they cannot be understood outside of this territorial dimension. As a result, we find some buildings of invaluable heritage and landscape value. However, the circumstances that have led to the richness of this heritage are those that, at the same time, generate the main problems for their protection. Identifying these Heritage places and their systematic digitizing will allow a better knowledge and their needs to be preserved, keeping their memory for posterity as most of them are in risk. We can distinguish between two functional types of these military constructions (Martín García et al., 1999): -The towers next to the no-man’s-land between these two kingdoms that controlled roads and natural paths where military raids could be carried out. Although there was no physical connection among them, the closest watchtowers were visually interconnected. In this way encoded information could be transferred from this first defensive line to other towers inside the Nasrid territory, and from there to the main centres. -These rear-guard border towers provided communication between the towers at the frontline and the intermediate fortresses and the main citadels, often creating a radial web. All of them were placed on hilltops for optimal visibility, at average distances between 5 and 7 km. Thus, the information gathered first-hand at the border could quickly be transmitted to the Alhambra in the Nasrid capital, Granada. In addition to this primary network, in that period there were secondary webs that fulfilled the same function for a given locality. Among them, we should highlight the farmstead towers, usually serving as the main stronghold of a small walled enclosure in order to protect farmers and cattle. The Castilians called them ‘cortijos’ (from Latin, cohors-cohortis, enclosure or corral). It is possible to divide the Nasrid border territory into several sectors. During the War of Granada (1482-1491) each strategic city that was conquered by the Catholic Kings (Isabella I of The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLII-2/W5, 2017 26th International CIPA Symposium 2017, 28 August–01 September 2017, Ottawa, Canada This contribution has been peer-reviewed. doi:10.5194/isprs-archives-XLII-2-W5-259-2017 | © Authors 2017. CC BY 4.0 License. 259