Automated analysis of high-resolution lidar traces large-scale medieval urbanism in highland Central Asia

Abstract

Aerial lidar (light detection and ranging) has emerged as a powerful technology for mapping archaeological urban landscapes, especially where dense vegetation obscures site visibility1,2. More recently, drone-based data recovery has drastically improved the resolution of lidar point clouds, allowing for slight traces of ancient structural features to be computationally detected at centimeters of detail across large sites, particularly in contexts of dynamic erosion such as mountains, where shifting soils irregularly bury and expose archaeological remains. Here we present the results of the first aerial (drone) lidar surveys conducted in Central Asia, collected at two newly discovered medieval sites in southeastern Uzbekistan: Tashbulak and Tugunbulak. Situated at elevations between 2000-2300 m.a.s.l, these urban sites illustrate a newly documented geography of large, high-altitude cities along the mountainous crossroads of Asia’s medieval Silk Routes (8th to 11th c. CE)3,4. Although hidden by centuries of erosion and sedimentation, our pairing of very high-resolution surface modeling with automated feature analysis produces a detailed plan of monumental architecture and fortifications spanning 120 hectares at Tugunbulak, revealing one of Central Asia's largest, high-altitude urban constellations documented above 2000 m.a.s.l.