Survey of a Peruvian Archaeological Site Using LiDAR and Photogrammetry: A Contribution to the Study of the Chachapoya

Abstract

In November of 2019, the company MEDS BV, based in the Netherlands but mainly active in the Americas, initiated experimental aerial remote sensing with airborne LiDAR imagery in the context of a private-public sector collaboration to enable identification of undocumented archaeological sites concealed beneath the high Andean tropical cloud forests in northern Peru’s Amazonas Region. Remote sensing fieldwork and post-processing application of Deep Learning methods by MEDS BV specialists, and subsequent analysis of DTM images by archaeologists yielded a remarkably detailed picture of a forest-covered, previously unstudied sector at the extensive archaeological complex of Kuelap called Imperio. At 3000 m above sea level, the Kuelap site complex consists of at least 12 sectors and two cliff cemeteries sprawling 900 hectares along a ridge top above the western banks of the Utcubamba River valley. Kuelap’s centerpiece and featured tourist attraction called “La Fortaleza” is a large settlement built atop a massive walled platform a long, prominent ridgetop. The Kuelap complex was probably the most populous locality in the Utcubamba River valley and is attributed to peoples that the Inka and Spaniards called “Chachapoya.” Early Spanish settlers left no known written descriptions of the site, nor useful descriptions regarding the region’s inhabitants. Consequently − and despite extensive archaeological studies − important questions concerning the political, economic, and religious roles of Kuelap in the region remain unresolved.

The project reported here has primary and secondary objectives, both resulting from multiple stages of data gathering, processing, analysis, and interpretation. The primary goal was to capture high-resolution, three-dimensional georeferenced imagery of archaeological remains hidden beneath the region’s dense tropical montane forests and provide sufficient data for a rich preliminary description. This work responds to the urgent need to identify, characterize, and protect such cultural heritage from looting and destructive activities that accompany population growth and deforestation. The second objective emerged as an unexpected bonus, only because of the extraordinary success of the first. Successful imaging of surface details at Imperio provided an extraordinary opportunity to reevaluate previous interpretations of the site, and to offer an alternative novel hypothesis regarding Imperio’s history of occupation and particularly the site’s special functions. The imagery enabled identification of subtle surface features that we suggest could be overlooked and inadvertently destroyed during conventional ground-level mapping and documentation activities in such complex, overgrown terrain. Many such features are functional elements of a planned drainage system that warrants further study for long-term conservation planning.