Quantifying spatiotemporal dynamics of urban growth modes in metropolitan cities of China: Beijing, Shanghai, Tianjin, and Guangzhou

Urban growth has been recognized to involve three main modes: infilling, edge expansion, and outlying growth. However, the relationship between three urban growth modes and their driving factors remains little investigated. To better address these problems and understand the general spatiotemporal dynamics of the urban landscape, the authors quantitatively analyzed the patterns of three urban growth modes in four metropolitan cities in China (i.e., Beijing, Shanghai, Tianjin, and Guangzhou) during a 20-year period through an integrated approach of remote sensing and landscape expansion index (LEI). The relationship between urban growth modes and three driving factors (i.e., city center, existing urban areas, and main roads) in each city was also investigated using buffering analysis and the area-weighted mean distance index (AWMDI). Results showed that these four cities had a significant increase of urban areas and developed different urban growth patterns. Despite different natural environments and social economy, the urban growth modes of four cities exhibit a common feature that edge expansion nearly dominated the growth mode during the study periods, indicating the urban growth across these cities tends to be the phase of coalescence. Besides, from the variations in the growth density (GD)-distance curves, each growth mode of the four cities generally showed exponential attenuation with the distance to existing urban areas and roads in each period, except for the outlying growth, which showed a stochastic and scattered pattern away from the city center and existing urban areas. Results from the AWMDI in each city also suggested that existing urban areas have a generally stronger effect on infilling growth than roads, whereas roads were a stronger attractor of outlying growth than existing urban areas. The findings of this study show an improved understanding of urban growth modes and help to provide an effective way for urban planning management.