The changing spatial form of cities in Western China

• Four western Chinese cities expanded 2% annually, 1988–2006, and 5–7%, 2006–2009.
• Chengdu, Xi’an, Kunming, and Urumqi, China, each more than doubled in size, 1988–2009.
• In Western China, one-third of new urban land is outside the core, in small towns.
• The results suggest a multinucleated urban form similar to coastal Chinese cities.
• Rates/amounts of expansion are highest in areas with tertiary residential activities.

Cities in China have exploded in size, population, and impact during the last three decades. The combined effects of liberalization, decentralization, rapid industrialization, and globalization have led to an unprecedented urban transformation. Several investigations have documented the land-based impacts of this transition, but the majority focus on coastal cities first targeted for reforms in the 1970s–1980s. Urban expansion and restructuring in China's western region have not been widely studied or well-understood. This research investigates the ongoing urban transformation in Western China (1988–2009), focusing on four cities: Chengdu, Xi’an, Kunming, and Urumqi. The analysis relies on land change maps, satellite images, socioeconomic data, and master plans, and draws on a variety of measures to estimate urban patterns through space and time. The results show that the pace of change is indeed high: all cities grew at annual rates near 2% from 1988 to 2000, but climbed to 5–7% after 2006. Each city has more than doubled in size during the study period, and nearly one-third of new urban land is outside the core, in small towns. This result suggests the emergence of a multinucleated or polycentric urban form consistent with trends reported for coastal cities. Analysis using landscape metrics along urban–rural gradients suggests that rates and amounts are highest in areas designated for tertiary activities and residential growth. Overall, the results suggest that urban expansion in Western China may not fit models of urban development based on U.S.-European cities, but aligns more closely with new models based on Chinese coastal cities.