Exploring changes in an emerging city of the Global South: a spatio-temporal analysis of built-up density in Hanoi

Abstract

Rapid urbanization in the Global South presents substantial challenges for sustainable development. This study conducts a spatio-temporal analysis of urban form morphology in Hanoi, Vietnam as a prime example of an emerging metropolis. A key methodological contribution of our work is the Relative Built-up Density index, a replicable and comparable proxy for urban density. This index integrates high-resolution land cover data with national population and housing census data. Our analysis uncovers a dual morphological trajectory. We observed intense vertical densification in saturated urban districts, often driven by the ‘residentialization’ of former industrial estates, alongside rapid horizontal expansion into suburban areas spurred by policies for New Urban Areas. This dual development has revealed a significant paradox. Although the average floor area per capita has impressively increased, this trend masks a severe housing affordability crisis. The Relative Built-up Density index is a valuable, low-cost tool for monitoring these nuanced changes in data-limited regions in the Global South. Our findings underscore the need for differentiated policy imperatives. The central urban districts require infrastructural retrofitting, whereas the sprawling periphery demands proactive planning to prevent future inequality.