Fig. 3

Xiaeryamakebu and Hongshanzui: (A) Aerial topographic view of Xiaeryamkebu, showing the stone walls; (B) Aerial topographic view of Hongshanzui; (C) Xiaeryamakebu stone wall; (D) Profile P2 in Hongshanzui; (E) Hongshanzui stone house wall; (F) Hongshanzui stone wall. Satellite images were taken by Y.H. using a DJI Inspire 2 drone, and modified using QGIS (https://www.osgeo.org/projects/qgis/).