Restoration of the distribution of pit-type Yaodong dwellings in the 1970s using US military reconnaissance satellite images in Luoyang Basin, China

Abstract

Yaodong is a traditional cave-type underground dwelling distributed in the rural Loess Plateau, China. It is widely found in the places where there is semi-arid, altitude is high, underground water level is deep, and loess deposits are thick. Particularly pit-type Yaodong is a form in which a rectangular pit is dug on the surface of the plateau, which is used as a courtyard, and a plurality of holes are excavated horizontally on the side of the pit. It is mainly observed in western Henan, the southern tip of northern Shaanxi, and eastern Gansu provinces.

Yaodong has various advantages suitable for the climate. For example, fluctuations in outside air temperature can be suppressed, creating an indoor environment that is “cool in summer and warm in winter.” Besides, Yaodong maintains a relatively steady indoor air temperature and therefore has an energy-saving effect. It can reduce energy consumption by about 40% and CO₂ emissions by about 60% compared to modern houses constructed on the ground. Moreover, the construction cost is reduced to about one-tenth of that of constructing a building on the ground, which contributes to reducing the economic burden on residents and sustaining resource utilization in areas with few trees. However, since the mid-1980s, when moving to a market-oriented economy progressed, the “New Rural Construction” movement aimed at reducing poverty, urbanization, and the rapid decrease of domestic farmland and flat land due to tree-planting campaign in mountainous areas and the demand for securing farmland on flatlands have led to the disappearance most of the pit-type Yaodongs and made it difficult to predict the situation at that time from the current landscape.

In this paper, therefore, we attempted to restore the distribution of pit-type Yaodong in the Luoyang Basin, Henan province in the 1970s by visually interpreting US military satellite images and using previous field survey data as a teacher. Furthermore, we examined the factors of Yaodong distribution, by analyzing the relationship between the restored Yaodong distribution and the altitude and topography on GIS. This study provides new knowledge from a geographical point of view on the architectural and cultural study of Yaodong and the loess plateau, by estimating in detail and extensively the number, distribution range, and distribution tendency of the pit-type Yaodong which is now lost and unknown. In addition, it provides the basic spatial information required for the evaluation of energy consumption and regional resource utilization associated with urbanization.