This study investigates the spatial gradients of urban land density (ULD) and nighttime light intensity (NLI) in 30 global megacities. Using the inverse-S function, it finds that both ULD and NLI decrease slowly near city centers, then decline rapidly in suburban areas, and finally decrease slowly again. NLI decreases faster than ULD, indicating a more pronounced spatial agglomeration of socioeconomic elements. This gap highlights the need for balanced development to avoid low-density urban sprawl and promote sustainable urban development.

Muchen Zheng, Wenli Huang, Gang Xu, Xi Li, Limin Jiao