Employment subcenters and polycentric urban development in the Greater Dhaka Region, Bangladesh

Although a significant number of studies have focused on urban growth patterns in Dhaka, the spatial structure of employment and its roles in shaping polycentric urban development is poorly understood. Specifically, how employment subcenters (ESCs) emerge and organize under conditions of informal and infrastructure-led urban growth typical of Global South megacities remains unclear. Hence, this study poses the question of how ESC formation is related with the construction and development of a polycentric urban employment structure in the city and how their hierarchical spatial organization shapes intra-urban agglomeration. To answer this question, the spatial distribution of employment in the Greater Dhaka Region during the 2011-2013 study period was analyzed based on fine-scale employment data from the 2013 economic census together with Local Moran's I (LMI) within a grid-based framework. An optimal grid size and shape were used to detect ESCs, including their location, hierarchy, spatial extent, geographical distribution, spatial characteristics and processes. The study found 59 ESCs, including one rank 1 center, four rank 2 centers, 18 rank 3 centers, and 36 rank four centers. The findings reveal a core-dominant but dispersed polycentric employment structure, in which high-ranked ESCs concentrated within approximately 20 km of Dhaka's historical core and low-ranked ESCs developed along major transportation corridors in peripheral areas. The findings suggest that the employment structure observed during the study period reflected a hierarchical, corridor-oriented pattern influenced by market forces and infrastructure-led urban processes rather than by planned decentralization, with weak metropolitan coordination strengthening the continued dominance of the historical core. These findings refine polycentricity theory for Global South contexts and provide evidence to support data-driven spatial planning and more balanced urban development in rapidly urbanizing regions.