The spatio-temporal dynamics of urban growth and population in metropolitan regions of Iran

The spatial configuration and the dynamics of urban physical growth are important topics of analysis in contemporary urban studies. This paper examined urban land expansion and population distribution evolution and their coupling in seven major Iranian metropolitan regions (pop>1M), and it contributes to understanding diverse urban physical growth patterns in the vast Global South. The analysis is based on an innovative approach of integrating two growth indices: a) ULE (urban land expansion) and b) PPE (population pattern evolution), applied to the demographic data and satellite imageries from 1990 to 2020. The findings show that population decentralization and land consumption have been significant over the previous three decades, although spatial growth patterns varied significantly across the chosen metropolitan regions. Furthermore, Iran's urban physical growth pattern goes from monocentric to polycentric, which is largely associated with the parent city's dominance. In fact, urban physical growth follows a concentrated-decentralization trend, with the latter spreading quicker than the former. Despite expectations, the infill growth has not essentially exposed to higher population density. This study's findings can help readers understand the urbanisation pattern and occurrence in Iran, and may assist policy-makers in understanding the physical impact of conflicting national executive policies, such as mass housing supply projects in urban edges versus inner-urban regeneration projects. In addition, it gives a major knowledge of the evolution of urban physical growth patterns, intra-city interactions, and growth drivers.