Up and out: A multifaceted approach to characterizing urbanization in Greater Saigon, 2000-2009

In this case study of Greater Saigon, two types of satellite data are used to estimate the rate of change in urban spatial expansion, both horizontally and volumetrically (horizontal and vertical components), and integrates them with socioeconomic data to examine the correlates and potential causes of both kinds of change. We employ new data products - the Global Human Settlement Layer (GHSL) derived largely from Landsat and a Dense Sampling Method (DSM) product based on QuikSCAT - in combination with data from the 1999 and 2009 censuses of Vietnam. Unlike past studies, we examine horizontal and volumetric changes in urban form and pay particular attention to the role of migration in locations experiencing those different types of change. We find these two types of urban change occur at different rates and in different localities, with the highest rates of horizontal change occurring to the north of administrative Saigon. In contrast, we find the highest rates of volumetric change in the areas north of the central districts but mostly within administrative Saigon. In-migration is strongly associated with horizontal change, whereas increases in population density appears to drive volumetric change, controlling for other factors. Positive volumetric change is associated with necessary amenities of modern urban living, often in high-rise buildings found in dense population centers like Saigon: the increasing presence in households of computers, air conditioners, piped water, and gas fuel. Use of these new integrated data hold promise to shed new light on both the built-environment and social dimensions of urbanization in low- and middle-income settings.