Quantify spatiotemporal patterns of urban growth in Hanoi using time series spatial metrics and urbanization gradient approach

Abstract

This paper combined multi-temporal remotely sensed data with landscape indices to investigate urban growth patterns of the Hanoi capital city of Vietnam from 1993 to 2010. Furthermore, the quantitative composition and distribution of the growth types were analyzed during the different periods. Afterwards, the distance effect on urban growth pattern from the center and fringe of urban patches was studied using buffering analysis. Our objectives were to quantify the speed, growth modes, and resultant changes in landscape pattern of urbanization and to examine the diffusion-coalescence and the landscape structural homogenization processes in Hanoi capital city. Cities in Vietnam have been experiencing major urban transition since the country adopted the economic reform in 1986 which introduce liberal market mechanisms, encouraging private-sector initiatives, while retaining the government's role as the nation's strategic planner and enforcer. Hanoi, one of the two largest economic centers, has been experiencing a progressive urbanization during the 17 years between 1993 and 2010. Using gradient approach, our study has shown that the rate of urban growth was higher in between 10 to 35 km buffer zones. The growth modes and landscape structure changes of urbanization were also comprehensively captured and described using the landscape expansion index and selected landscape metrics. The process of urbanization was characterized by relative dominance of infilling, edge expansion, and spontaneous growth modes across the landscape. Our observation of the Hanoi urbanization in 17 year period could support the diffusion and coalescence phase dynamics. In addition, periodicity in the growing process, and the regularities of the shift of growth hot-zone revealed in this paper could be important implications for urban modeling and prediction. Through our landscape pattern analysis and comparison with other cities, it revealed that the urbanization of Hanoi is limited by its infrastructure systems which make the urban growth not evenly distributed, limiting their competitive advantage, disproportionately high transport costs, growing congestion and land market distortions. Therefore, strategic urbanization plan for future should consider improving urban transport and infrastructure systems, as well as strengthening its competitiveness in the region.