Characterization of spatial and temporal evolution of earthen sites construction technology in China based on GIS

Chinese earthen sites are notable for their abundance, historical depth, and cultural value, with construction techniques diversifying from Prehistory to the Qing Dynasty. However, existing research has yet to provide a comprehensive quantitative analysis of the spatial and temporal evolution of construction techniques at earthen sites. This study identifies eight key techniques, including cut left, rammed earth, adobe, wattle and daub, cob, stacked earth, grass-wrapped mud, and mixed soil-rock structure. their evolution was delineated into five phases: (Ⅰ) Embryonic (Before 2070 B.C.), (Ⅱ) Development (2070 B.C.-221 B.C.), (Ⅲ) Formation (221 B.C.-618 A.D.), (Ⅳ) Application (618 A.D.-1206 A.D.), and (Ⅴ) Transformation (1206 A.D.-1911 A.D.). Spatial analysis using ArcGIS Pro tools uncovered a "concentration-diffusion" pattern: rammed earth techniques radiated from the Central Plains, stacked earth clustered along the Yellow and Yangtze Rivers, and cut left prevailed in early civilization regions. Quantitatively, cut left dominated the Embryonic phase (41.5%), while rammed earth usage escalated from 78.5% to 91.5% across subsequent phases, marginalizing other methods. By the Transformation phase, only four techniques persisted at 47 sites, with masonry and wood displacing earthen structures. The spatiotemporal evolution reflects dual drivers: natural factors (climate, soil, topography) and societal dynamics (productivity advances, demand shifts), epitomizing the dialectical human- environment relationship. This synthesis of technical progression and environmental adaptation not only clarifies historical construction practices but also informs contemporary strategies for heritage preservation. The findings underscore how ecological constraints and human ingenuity jointly shaped architectural innovation, offering vital insights for heritage conservation and historical research.